While me as well as my family have owned plenty of BMW's over the last 20+ years, my E85 M is the first time either of us have had a "Zed" car. I've never managed to go in a Z3, even though I have a soft spot for the Z3M.That could be right as mine was a facelift E85. Not sure about the difference between the 2.5 and the 3.0, mine had the N52 engine and I think about 215 bhp.
I could not get on with the Z4 so sold it and got another Z3.
About 10 years ago, a friend of mine who worked at the Mini factory, bought an E86 3.0 and took me out in it. From that moment I kinda feel in love with the Z4. If it wasn't for the fact my dad had to give up with E46 M3 Individual Cab last summer, I don't think I would have been so keen to get myself a Z4M, as I really love the sound the S54 makes.
As a rule of thumb, I've always preferred the Coupe versions over the soft top. With dad's M3 being a cab, you could really notice that it was lacking a sharpness and edge the M3 Coupe's have. The extra weight and the rattles from the frame of the soft top really were things that put me off ever wanting to own a cab. When I decided to get a Z4M, I wasn't able to stretch the budget to get myself an E86 M, so I ended up looking at E85 M's and E86 3.0's. Once I started to do more research on the E85 and E86 M's, I was pleasantly surprised to discover that there was no weight penalty for having the roadster and thanks to the Z4 being designed as a roadster first, the chassis was stiff enough that people were telling me, that with road driving, I would never be able to push an E85 M hard enough that the chassis stiffness would seem lacking.
With me being over 6'4" and with a lot of lower spinal damage/injuries, I tend to only go for 2 door cars, as you typically have a much longer door, which makes it easier for me to get in and out of a car. I knew the E86 was a bit roomier inside than the E85, so I decided to find one as close to Oxford as possible and see if I could fit in. In the end, I actually bought the car I tried out a few weeks later and managed to get a much improved deal from the dealer I bought it from. On the drive home, I was having issues seeing the speedo clearly, so after playing with my seating position, I have the rear reclined way more than I normally would have in my previous cars, which has ended up with me discovering a seating position that totally removes any compression on the damaged sections on the base of my spine. When my back is hurting me, I've gone out in my M and after 20 mins the pain has dulled enough that it's not an issue any more.
With the Z3M's smaller size, I don't think I would be able to fit inside one, without having issues flair up with my back. I had stopped driving for a few years, as my health declined pretty badly and even though I owned an amazing car, it ended up just rotting away on our driveway, so I sold it with a heavy heart. I only started driving again in July, after I had my annual back treatment. I was driving my mum 2010 factory JCW Mini, which while being an utterly blast to hoon and bomb about in, was just not suited to someone my size. Due to the upright position you drive in, I was having problems being low enough in the car to be able to look up at signs/traffic lights etc at junctions. One thing I learnt about the Z4 and the M's, was it had a very low seating position, which is just perfect for me.
I never thought I would like/love a car more than I did with my heavily moddified Subaru Impreza P1, but within days of owning my E85 M, I had become even more smitten than I ever had with the Impreza. As I said in an earlier post, the M has some flaws, but overall I can't think of a better car to have bought, for the budget I had and the various requirements I had and a number of conditions my mum had when getting me a car after 3 years since I had my Impreza.