Well, I'm sure on the subject of cars we'd find a lot of agreement - I had a Z4!!
Originally Posted by Z4luvr
+1 (Can't believe I am agreeing so easily with EDCT!) I use my 3.0Si as my daily driver, sometimes in significant traffic. While the M might be more sporty and fun to drive, I never really considered it due to the beating it would be in traffic. I really like the 18 inch wheels and overall wider feel of the Si VS the 3.0. I also like the look of the sport wheels that come when you get the sport and premium package (which is how many are equipped).
The prices you are talking about seem pretty high. I bought my 2006 3.0si in 2009 with only 17K miles for 28K with a CPO warranty and waiving a lot of excess wear and tear on my previous Z4.
If I were looking at a used Z4 I would look to the new model design for a CPO xdrive 35. My son's xdrive 3.0 compares favorably to my Si, but adding the turbo makes that Z4 a beast with no need to add an M to it. It's already a ticket machine, but if it had the turbo, he might be in jail permanently.
2000 Mercedes Benz E320 (daily driver)
2007 Infiniti M35x (wife's)
2006 330 cic ZHP 6sp (current)
2005 Z4 3.0 sp nav x-leather (retired)
2000 323i PP (best car, ever - retired)