new to euro tuning, need advice

I am interested into getting into Euro tuning and i need to bounce some ideas off of someone on what car to get. I've never owned a Euro before but have always been fascinated by their beauty and performance, i've owned a 93 Mitsubishi 3000 GT and even tuned a Ford F-150 but now im ready to sell the truck and do it all over again lol. I have been looking into the BMW E46. I was wondering which of these would be a good choice for performance and availbilty of parts. Should I look into the 328, 330, or just get into the M3? Im absolutely in love with the M3 and i have found them used for around $15K with 70k+ miles, are these engines reliable for high miles? I need all the advice I can get, I have big plans for this vehicle. I'll be working on a budget but thats what makes a starving artist, right? Thanks for your time