The whole "it's better to drive a slow car fast than a fast car slow" is one of those old car-guy adages that bugs the crap out of me. We've heard this to death already, and it's nonsense.
There's a short set of curvy switchbacks on Sheridan Road (conveniently right between work and home) and I can tell you that when nobody's in front of you, it's fun to drive that in any performance-oriented car. In a non-performance car, it sucks. When my Abarth was in for some service, I got one of those new not-fast Ford Focii as a loaner and it was TERRIBLE going through there. The car simply did not want to be doing what I was asking it to do, and I wasn't even pushing it. Better to drive a slow car fast? Not in this situation.
Driving through those same switchbacks in the Abarth is the same amount of fun as in my 911. There's no question the 911 is a faster car. There's a slight advantage to the Fiat here because of the noises it makes, but there's an equally slight advantage for the 911 because nothing else feels quite like a 911 when you're squirting out of a tight corner. I'll call that one a tie.
Up in the Kettle Moraine area, there's some decent driving. Here, too, the driving is about equal no matter what sports car you're in. I've had Miatae up here, Porsches, Mustangs, BMWs, the one Corvette I had, and all of them were probably more or less equally fun to drive. Slow car fast, fast car fast, fast car slow, slow car slow, you'll get as much of it as the northern midwest can give you (admittedly, not much). But in a E36 M3ty car, it's a E36 M3ty drive.
The whole slow-car-fast thing always seems to be to be an excuse for driving a cheap, slow car, when no excuse is remotely necessary! If you have a car that you like, good for you! It doesn't matter to me whether it's slow or fast or cheap or expensive. It's like these guys saying "the E30 is the last real 3-series!" Yeah, until you can afford an E46, then that will be the last "real" 3-series. We need to stop justifying ourselves and start enjoying ourselves.
I think I probably do it a little bit, too. I have a 997 C4. The reason I don't have a C4S or a Turbo is mostly because those were more money than I wanted to spend. I don't really need the extra speed of an S or a Turbo - the C4 is plenty capable and fun on its merit. But I sure would love to have more! But I have no "wisdom" to justify my slower car purchase. It's not better to drive the slow car fast.
I understand it more in the motorcycle world. I had a Ducati 999S and a Ninja 250R at the same time, and, honestly, on the street I far preferred the Ninja. I would whack the throttle open and not go to jail. The tires were skinny and I could actually lean the thing over. The Ducati wanted to RUN, all the time. It always reminded me of the T-Rex in Jurassic Park. "T-Rex doesn't want to be fed. T-Rex wants to hunt!" The Ninja didn't care. It was like a puppy. It was happy just to be outside!
Cars, though, don't usually come like that. Commuting on the 999 was miserable. Commuting in a GT3 or a Z06 is totally tolerable.
Get the car you want, and drive it how you want. Don't coin an axiom to impress us all with your choices.