Mine is education. For me it is the journey not the end product; that's a byproduct. Education requires doing interesting things, which then involves rubbing shoulders with interesting people (who do interesting things). A lot of education is by osmosis.
I know old school BMWs like the back of my hand - lots of 2002s, E30 M3s, E28 M5s, E34/E36/E46/... . I did not know the turbo platform(s) or newer chassises. Ironically I had owned and wrenched on a good number of turbo cars - 2.3l ford, Audi S6, endurance raced 300ZX's, etc. I purchased the E89 Z4 to walk down that path and
do something a little different.
I set a target of getting to 600whp with 100k miles street car reliability, behavior, etc - so that has kept me busy. That's with a full race suspension on the street - today's chassis is so torsionally rigid that with the right setup one can have that kind of handling performance without losing much suspension comfort. I believe with the right set-up, tune, maintenance, and driving behavior (non-Neanderthal), one can achieve such a build.
All you turbo guys might think 600whp/100k objective is meaningless, especially if you drag - but from the road race world I come from that's a really spectacular achievement on a BMW platform. One other thing by passing observation: I've found that a lot of BMW turbo guys are actually from other turbo platforms. They don't come from 20-30 years of BMW ownership. That's been really interesting - to realize there is a horizontal group as opposed to a vertical brand group. I'm still understanding what cross-pollination (and blind spots) that brings. That said, for those of you that are not lifelong BMW guys, there is a whole world of BMW enthusiasts that are uneducated about this platform ... and if they only knew ...
The time I've put in (research, comms, wrenching, testing) has blown away the amount of $$$ put in. The journey has been a blast. I've gotten to rekindle what was a old, passing friendship with
@barry@3DM and meet some new people (
@jts1981 , Dimitri
@BQTuning ,
@Asbjorn ,
@Lurcher ,
@NoQuarter , ...). Can't say I made the wrong choice.
If you are looking at just what happens when you step on the pedal or turn the steering wheel, buy an M2 - that should do it all well.
Filippo