You might wanna check Dynaudio website, they are still very active in aftermarket world. Their Esotars2 drivers are one of the most desirable drivers with SQ guys. Will make hear stuff you've never heard before.
There's plenty of options out there. Focal, Rainbow, DLS, Audio System etc all make speakers that fit in stock locations.
Regarding the kick panels, I guess you've never heard a system with kick panels. You'll be suprised what Time alignment can do. My car is a car audio competition car, competes with the best in the country. I have a 530i, not really a perfomance car.