honestly from what i know there is no difference. as long as the tuner is able to get the desired result.
but the problem is, the price gap is small. and custom ones u'll need to trade ur current ones to be done. and works out being similar in pricing.
b4 aerospeed came abts with these cam pulleys, all racers and similar customed the cam pulleys and i've not heard much of any issues abt them.
call me 012 2261306, i still want to make u a deal for the loss opportunity to deal with u