BMW Z4M r vs Z4 3.0si r
Discussion
Hi everyone,
I'm looking to get myself a z4 e85 with a bit of power.
I understand that the Z4 3.0si is cheaper to buy, run and is a lot more reliable. My bank would prefer this option. However, my heart would love the Z4M, but I hear horror stories about the S54's rod bearings and the general cost of maintenance.
I wanted to hear some thoughts on these comparisons.
Is the extra money worth it?
I'm looking to get myself a z4 e85 with a bit of power.
I understand that the Z4 3.0si is cheaper to buy, run and is a lot more reliable. My bank would prefer this option. However, my heart would love the Z4M, but I hear horror stories about the S54's rod bearings and the general cost of maintenance.
I wanted to hear some thoughts on these comparisons.
Is the extra money worth it?
I owned an M54 3.0i for a few months and recently went through this same conundrum, and came within a hair's breath of buying a 3.0si roadster.
I've owned lots of cars over the years, but that M54 is a cracker. The S54 is meant to be strong in the higher rev ranges, expensive to run and comes with an unresolved suspension set up. So, I think the SI is the one to have for the street.
For some reason, though, the market doesn't value the roadsters, as good as they are. So you should be able to pick up a decent one for around £6k.I rate the 3.0 Z4 highly - above a 986 Boxster, and even an S2000, but the market doesn't agree.
The one to have is the coupe in 3.0si manual guise. Get a decent low mileage one at a reasonable price and it'll hold it's value over time.
I've owned lots of cars over the years, but that M54 is a cracker. The S54 is meant to be strong in the higher rev ranges, expensive to run and comes with an unresolved suspension set up. So, I think the SI is the one to have for the street.
For some reason, though, the market doesn't value the roadsters, as good as they are. So you should be able to pick up a decent one for around £6k.I rate the 3.0 Z4 highly - above a 986 Boxster, and even an S2000, but the market doesn't agree.
The one to have is the coupe in 3.0si manual guise. Get a decent low mileage one at a reasonable price and it'll hold it's value over time.
Good points both. Although the M is what I really want, in my position the sensible option is to go for the Si.
For reference these are the two I am debating...
https://www.pistonheads.com/buy/listing/20209040
https://www.tradeclassics.com/classifieds/bmw/2007...
For reference these are the two I am debating...
https://www.pistonheads.com/buy/listing/20209040
https://www.tradeclassics.com/classifieds/bmw/2007...
I went from an e46 m3 to a 3.0si z4, both coupes.
Just didn’t love the Z4 after the m3. Engine and ride quality were incomparable unfortunately. Steering on z4 is also pretty dull.
Straight to the 3.0 si it’ll likely feel good but I’d suggest the two you are comparing are not really comparable once you’ve driven the m.
Just didn’t love the Z4 after the m3. Engine and ride quality were incomparable unfortunately. Steering on z4 is also pretty dull.
Straight to the 3.0 si it’ll likely feel good but I’d suggest the two you are comparing are not really comparable once you’ve driven the m.
Maxxatron said:
Good points both. Although the M is what I really want, in my position the sensible option is to go for the Si.
For reference these are the two I am debating...
https://www.pistonheads.com/buy/listing/20209040
https://www.tradeclassics.com/classifieds/bmw/2007...
Both fab cars. I called the owner of the SI as I fancied the car. It has KW V1 Coilovers and has been well maintained. I’d have gone to view it has he not been waiting on a viewing - a no show as it turned out, but I’ve since bought a Cayman. For reference these are the two I am debating...
https://www.pistonheads.com/buy/listing/20209040
https://www.tradeclassics.com/classifieds/bmw/2007...
The M has been around for awhile but looks fantastic.
You can’t go wrong either way.
Maxxatron said:
How was that Si in general?
The owner came across as genuine and honest. He’s had a few time wasters so if you can get it for £7500, tidy it up a bit, I don’t think you’ll lose come resale. The M is the better car of the 2 on paper, but when you factor in the purchase price, VED, mpg, resale, etc. in reality there’s not much in it.
Given that you want a roadster, the M is probably the one to buy, otherwise you’ll hanker after one.
I had a 3.0Si Coupe for over 5 years and loved it, but then I got the chance buy a Z4M Coupe for a sensible price in 2019 and it was an itch I just had to scratch. 6 years on and I'm still loving it, even more than the 3.0Si. 
I got the rod bearing shells replaced soon after I bought it at 78K miles as a preventative measure. That probably costs about £1,500 now at a good BMW Indy. Every other service is an "Inspection" service which on the M involves checking the valve clearances on a cold engine then adjusting them with shims as unlike the 3 litre the M doesn't have hydraulic lifters. That costs £600/700 each time. Any other parts like brakes are also subject to the "M" tax, then there is the £760 a year Road Tax.
I knew all this before I bought mine and it's a price I don't mind paying because it just makes me smile as soon as I start the engine, but you really need to go into buying one with your eyes open. Mine is only used as a fun car and typically only does 3 or 4 thousand miles a year so those Inspection services only come around every 4 years, with a simple oil service in between.
Other differences are that the M has Hydraulic PAS which has more feel than the Electric PAS on the 3 litre although it is a bit heavier. It also has an LSD and doesn't come with run-flat tyres, although plenty of owners put normal tyres on non-Ms.
They are also quite rare as only just over 1,200 Z4Ms came to the UK, split roughly 50/50 between Coupes and Roadsters.
I still think the 3.0Si is 80% of the car for about 50% of the price, and it's much cheaper to run so would be my choice for a daily driver. They still perform pretty well and have a lovely straight 6 engine that revs freely all the way to the 7,000rpm red-line.
If the 3.0Si makes more sense for your planned use/budget just don't go and try an M, because once you experience an S54 engine howling up to its' 8,000rpm red-line you'll want one!
It's worth doing a bit of research on a dedicated website like z4forum.
Anyway good luck whichever you decide to go for.

I got the rod bearing shells replaced soon after I bought it at 78K miles as a preventative measure. That probably costs about £1,500 now at a good BMW Indy. Every other service is an "Inspection" service which on the M involves checking the valve clearances on a cold engine then adjusting them with shims as unlike the 3 litre the M doesn't have hydraulic lifters. That costs £600/700 each time. Any other parts like brakes are also subject to the "M" tax, then there is the £760 a year Road Tax.
I knew all this before I bought mine and it's a price I don't mind paying because it just makes me smile as soon as I start the engine, but you really need to go into buying one with your eyes open. Mine is only used as a fun car and typically only does 3 or 4 thousand miles a year so those Inspection services only come around every 4 years, with a simple oil service in between.
Other differences are that the M has Hydraulic PAS which has more feel than the Electric PAS on the 3 litre although it is a bit heavier. It also has an LSD and doesn't come with run-flat tyres, although plenty of owners put normal tyres on non-Ms.
They are also quite rare as only just over 1,200 Z4Ms came to the UK, split roughly 50/50 between Coupes and Roadsters.
I still think the 3.0Si is 80% of the car for about 50% of the price, and it's much cheaper to run so would be my choice for a daily driver. They still perform pretty well and have a lovely straight 6 engine that revs freely all the way to the 7,000rpm red-line.
If the 3.0Si makes more sense for your planned use/budget just don't go and try an M, because once you experience an S54 engine howling up to its' 8,000rpm red-line you'll want one!
It's worth doing a bit of research on a dedicated website like z4forum.
Anyway good luck whichever you decide to go for.
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