Ive had AP coilovers. Great in Germany on nice smooth roads rated them really highly, that was until i moved back to the UK where i done a 180o turn with my opinion as they are crap on UK roads on our roads. I wouldnt buy them, or any other cheap coilover brand again.
Buy nice or pay twice. Simple as that.
I also really dont rate KW Coilovers. EVERY car I have tried with them have been border line unbearable. Go for Bilstein or AST instead IMO. Then theres the issues with KW quality that are becoming more and more evident.
The reason KW are so popular IMO, is they get to the market first, so secure the largest share of the forums, so when people ask what to get....the answer is KW. That is until the competition release they're kits.