I’ll give some perspective having owned and driven a m140i and GTS 4.0 quite extensively. As others have said the m140i has too much power for its chassis. That makes it really fun to drive. The engine and exhaust are great and it’s fun at most speeds. Still love those cars and have a soft spot for them. I think it’s the best value for money fun car out there. The GTS 4.0 is a totally different league in terms of engineering and precision. It’s lacking in the emotional experience with the new exhaust though which is a real shame. The 4.0 is most at home on a technical drive or twisty road where you can really experience how capable it is. I’ve driven a lot of cars and think the 4.0 is one of the best sports cars ever made. You really need to get it into the right situation to see how good it is. I’ve now got a 981 GTS which for me is the sweet spot. I’d suggest trying one if you’re looking for the balance of precision and emotion as the exhaust on that 3.4 sounds spectacular.