I disagree. There is no way stiffer springs don’t change ride comfort, and you need to properly match lowering springs to a more aggressively strut for it to work, so what you said doesn’t work...
It’s true that a rear sway bar will cause oversteer, but that’s simply not an issue with a stable vehicle like Mazdas. I am an experienced driver, and based on my findings from all my time driving I would happily rather control oversteer VS. understeer. Rear axle drifting is very easy to control VS. Full on understeer, and ultimately you have more control over the vehicles angle via throttle and steering input VS. Understeer, where you have to let go of the throttle and pray you don’t smack a curb.
If you are an experienced or confident driver, oversteer without a doubt is what you want. The idea with the rear LSD is a really good suggestion, and I highly recommend that.
But for $500 modifications, you’re best off buying front/rear sway bars and some camber plates rather than lowering springs.
Mazda uses a form of body roll mainly on purpose to give the driver a sense how how hard they are pushing the vehicle. It’s also partly because they have not advanced their chassis design to a point where the chassis itself can soak up bumps without the need of soft suspension, so body roll is minimal (etc Volkswagen or Acura) Personally, I’ve pushed my Mazda 6 sedan hard enough to see lots of body roll (although it was still very composed and controlled) so I can only imagine how much worse the roll is on the higher-up crossover... it does not corner flat despite the fact that it’s such a stable and fun to drive quickly.
Aftermarket suspension absolutely does not mean that you are going to suffer from a stiff or uncomfortable ride. Bilstein struts are not available for the CX-5 unfortunately, but they offer an excellent blend of street comfort and performance. when you strike the correct balance with a suspension suited to the chassis in your vehicle you will not have a car that rides stiff. The same goes for coilovers such as BC racing. They are fully adjustable, meaning that if you take them to a competent shop who can precisely adjust ride height, damping etc the coilovers might as well just start to ride BETTER than the OEM shocks you’ve had before.
Funny how you mentioned that the suspension in your ZR1 is too expensive to fit into a Mazda, but we’re talking about a Chevrolet here... the irony...