Infinity Kappa 10 is the best sql sub for price. Don't go for 8 inch. It sounds nice at some volumes but misses out the lows on others. Dual 10" is perfect size for sedan. If you are not looking at active setup immediately, try the Infinity Kappa 50.11cs for front doors. Amazingly good mids and highs. Disconnect rear door for some time and spin around and see. Probably a 6" kappa co-axial for lower mid bass punch on rear doors.