G20 3 Series - ICE upgrade

[Zippee]

I've recently purchased a 22 plate M340i, great price and approved used but also basic spec (not bothered with packs as they are pretty well equipped standard). However, it does mean no HK stereo.
I'll be reaching out to a few ICE installers near me but has anyone on here upgraded the base stereo themselves? If so what did you change (Just speakers or amps, subs etc) and what sort of cost was it?
I want it to look as standard as possible but with better sound than the HK everyone goes on about.

[sortedcossie]

It might void the approved used warranty, that might not bother you though.

[rottenegg]

It will indeed bust the warranty.

ICE in post 2015 BMWs is a massive rabbit hole.

Just get the entire HK setup from a donor car and get someone to code it in for you. HK is plenty good enough for most people, but swapping the HK amp out for the Bimmertech Lightwave one is apparently a good upgrade, but it costs 2 grand.

As I say, rabbit hole. An expensive one.

[Dannbodge]

You'll be able to buy replacement underseat subs, speakers and plug and play amplifier.

Vibe and Match do systems that are probably compatible, and easily installed/removed.

There are people that have upgraded base spec G30s, so the equipment wil be similar if not the same.

[Zippee]

Thanks all, I'm not talking about the head unit, just speakers and an amp - is that really going to potentially cause the issues you mention?

[bigdom]

Replace the front door & under seat speakers with Audison, their amps also play nicely with the BMW optical loop. The Bmw system can take care of the rears.

If you can forgo some boot space, this would work, or just omit the sub- https://caraudiosecurity.com/bmw-4-component-speak...