I have JOMs on the back and they are no worse then the APs i have at the front (Even though they are £100 each!)
Altough neither compare to the SPAX spring and shock setup i had with adjustable dampering, they were sweet!
To be fair suspension itself wont improve the way it handles my more between brands. You will need poly bushes and anti roll bars.
My friends VR6 had chopped springs on standard shocks (Now on coilovers!) but with the anti roll bar it could fly round corners!