Boyo said:
I currently have a 65 plate 35is which I bought about 20 months ago as an AUC. The car has been faultless and I have really enjoyed it. Prior to the 35is, I had a beautiful low mileage MR, which I ran for three years. A part of me is missing the interaction of the MR and I am toying with going back to one, however, I am not sure whether I will regret it. My daily drive is split between a 140i and a Lupo GTI, depending on what I am doing so. Any thoughts would be welcome.
I reckon the 35is would feel subjectively quicker even if it isn't, same for the 140i but I haven't driven either and a mate from work who's had a 1M, F10 M5 and currently a 140i raves about it! For me though, the Z4m is about the slightly analogue feel, manual box, awesome NA S54 etc. Mine is a weekender (Z4MC though) and I can never wait to get back into it! The Gruppe M seriously enhances the experience for me as well, as does the Bilstein set up. Everyone knows they're flawed and the ride and gearbox could be better but get them sliding on a wet roundabout and it's grin time

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They look awesome and would probably be a much better financial decision as well. You've probably guessed that I'd say go for it!
BTW, I'd love the other members from our neck of the woods (South Wales) to arrange a good Sunday run, you could reacquaint yourself with them before making a decision.