According to the APR website, stock to lightly modified cars should replace the sub frame mount, heavier levels of tuning should consider engine and transmission mounts too. Apparently.
Polybushing will always make for a tighter ride. You can buy a whole car kit from Awesome GTI for under £600, but for about 2.5 - 3 times that you can pay someone else to do it for you. The latter will be my preference.