I'm running my ph1 on sportlines and the front dropped 15mm and rear 10mm, so not much of a drop at all. The sportlines are suppose to lower more so I guess prolines would not lower at all.
Prolines are suppose to have better handling but not drop much and sportlines are stiffer and bigger drop.
I used sporlines for a track day and they were ok, could of beniffed from stiffer dampers.
Eibach are the best out the box springs to go for if your on a budget. They work well with Koni dampers to.