Manual RWD V8 with a loud exhaust is far from dull, trust me
I didn't hate anything about my 350, once I'd finished modifying it, and if it hadn't been for the opportunity to move in to the 911 I'd have kept it for many years. It's just that everything the Zed does, the 6er does too, but slightly better. I'd definitely not categorise the 6 series as a sports car though, waaaaaay more a sporty GT.
Comfy on the long run? Check. Fuel economy? Better on the V8. Noise? Not even close. Gearshift? The BMW has the better 'box. Steering? Actually, this one is a draw, but only because the 645 can tighten the steering as otherwise the Zed would have this category. Outright pace? Nowt in it, 6er pulls better from low down and pulls harder at the top end. Sliding? Okay, easy win for the Zed, the BMW has no LSD!
That said, if I didn't have the MR2 I wouldn't enjoy the BMW as much. It's only because I still have the proper sports car in the garage that I can enjoy the BMW as much as I do, as otherwise it would be a little too big and heavy for an only car. The 350Z is absolutely amazing and I miss mine so much, and came *this close* to buying another instead of the 645. But, y'know, V8.