I agree fully with the tinkering, but in my opinion, turboing a car that wasn't factory turbo'd isn't tinkering.
I've tinkered with my Clio, full suspension and a cage with buckets and it's just as much fun as I can imagine, not convinced I want any more power.
Saying all this, doesn't mean I don't think you should do it. I think boosted Clios are epic, I just don't think it's for me.
I'm just not convinced an e46 M3 is a good investment when I don't have a house...