Advice needed with an e46 mod

[indee321]

Hi guys this is my first post here on pistonheads ive read some really good advice and opinions over the last 6 months so thought it was about time i joined in. I know this question has been asked before as ive read and researched as much about it as i can find, but i dont seem to be able to find a good quality 'defininitive' answer.. so here goes

I habe recently bought a 1999 saloon e46 323i. Its immaculate with only 60k on the clock.. so please no ' buy a bigger engine' as im very happy with it.

its an M52TU engine and ive already exchanged the inlet manifold for an M54B30. I would like to know what i can now do with the exhaust sytem to complete the mod. All i would ultimately like to try and do it gain similar hp and torque as the 325i which shouldnt be impossible as they are the same engine capacity. I dont think realistically i will be changing the dif.

I realise the intake and exhaust mod alone wont do this.. the last thing i will do after all mods is rolling road and tune the software.

The 'headers' are restrictive and they contain the cats on these cars so removing them isnt an option for me but as i understand it the e46 323i standard header is the same size as the 328i,is that correct? If it is , there isnt really a great deal of point in going sport or bigger tubing etc as its unlikely i'll be getting anywhere near 328i levels of hp / torque, agreed?

So what are my options for the exhaust from the standard header back? the 323i M52TU is a little unique therefor limited in options? I am wondering what other standard exhausts would replace mine. Is a 328i M52TU exhaust a direct replacement? Or can i use something from the the M54 range, maybe even the whole system including the headers?

Any help much apreciated

[indee321]

Thanks for the reply.. so when you say i can swap the cat manifolds for no cat ones.. that means i would need to find a system that has the cats fitted further down the exhaust pipeline right? I dont want to go 'catless' too much hassle at MOT time.
This is why im trying to gain info on an alternative BMW standard exhaust system , say the 328 m52tu .. is that a single or fully duel piped system?
I'll def look into the 330 inlet cam , not heard of that one before.
Has anyone else got any advice about what alternative bmw factory fitted exhaust will fit to allow a better tune up ?

[indee321]

and this is the 323 .. hmm does anyone know if the 328 exhaust manifold will be able to replace mine? Obviously the two systems are quite different , im just wondering why and if there is a bennefit in terms of performance to put a complete 328i onto mine if it will fit..

[indee321]

Yes comparing the two exhausts i think your right.. someone has suggested to me this exhaust system and it seems reasonably priced. The schmiedmann scm5254 looks like it might just be the option i go for with a little saving up

[indee321]

yep.. the more i look at this the more i feel like its a good option ., just depends on the expense to fit !