Should I do it.........?

[Dino D]

I think if it can be done at 5k or less that's pretty interesting. Given if you bought an actual //M and wanted a full custom paint job again you'd probably spend 3-4K on the paint job and cosmetics alone.

Maybe get the engine bought and work it out from there and find a garage that can do it over winter, gives you time to source everything and then let them do it with no time pressure which could help costs.
You can also have the head gasket checked and bearings with the engine out, apparently becoming a common issue in the S54 from my research into e46 M3's.

 

[bertiejaffa]

I don't know if it is possible or what can be done or how to do it etc. However, my thoughts on the question are that all the threads I have ever read about cars with different engines are awesome....

HOWEVER... they are all done by people who (1) have lots of money, (2) have either the knowledge to build bespoke solutions or (2a) have garages that will take more of (1) to build bespoke solutions.

In (my) conclusion, its a great idea and I know its tempting because I looked into it with my old 2.0l Z3... the reality is that having a half and half (ie doing just enough to make it work) will ensure that it will be unique, but it will cost a lot to do and will cost even more to maintain as no garage will be able to research the information unless you change everything to an M setup in which case buying an M would be the cheaper and easier way.

I'm sure that probably hasn't helped.... but your car is stunning - I reckon you could sell yours for a premium and buy an old M, and do it up (even dropping in your mates engine) for less than this will cost.

 

[Anakin]

Few thoughts, any money you throw at the current car doing these mods will probably disapear if you ever wanted to sell it it may even be worth less, as things like insurance would be more complicated. Bolt on mods come off and can be sold on if you keep the parts you are replacing. If your not doing this your self then its going to cost you. A M car will have more than just M engine and gearbox, I'm not sure what you have already upgraded on your car but some of it might need upgrading as well.

My choices in order would be
1- Leave it alone and enjoy.
2- buy a M
3- Supercharge it
4- Do the Engine swap

 

[Anakin]

5- Do the Engine Swap and Supercharge it

 

[Mac Romans]

I like number 5.... but number 1 is much more affordable!

 

[Mac Romans]

I've had a change in circumstances recently so the sensible thing is to hold off.....for now at least.

 

[Paul Rice]

Hmmm...it's something to think about. The wiring loom and possibly ECU will come with it along with the gearbox. He's offered me the lot for £2000 which is well below the going rate.

Your Z4 quick enough mate, Buy an old basic 3 series, transplant engine etc. and have fun with it as a track car.