Bought my M44 six years ago and went through the same buyer's remorse you are. I am 57 years old now for what it's worth. A friend has a Mazda 3 turbo. Even though I am behind on HP, he can't stay with me in tight corners. Z3M44 has excellent weight ratio from center point forward and center point reward, 49/51 I believe. It sticks to the road like glue. When he jumps on the accelerator there is a lot of torque steer from the turbo pulling the car to the right. I prefer the rear wheel drive of the Z3. And as already stated repair costs are much less expensive. Mine is a 1998. I have had it up to 130 mph with the top down.
Put your money into keeping the M44 running in top running condition and replace bushings, shocks, suspension parts and you will have a great experience.
Only negative is I am an introvert. I drive it daily totalling 300 plus miles a week. At least 1 or 2 times a week someone wants to come over and tell me what a beautiful car I have. BMW made it, I just keep it clean and running but I will tell them what they want to hear and say thank you.
If you made it this far reading my post, you can tell, I have NO REGRETS BUYING A Z3M44.
Enjoy yours,
Marvin