Here's some measurements I made w/ my setup (Koni's/STi Tarmac springs/RCE front plates)
First I found out the Koni's have a little longer stroke than the oe struts (albit minor)- 5mm up front and 10mm in the rear. Secondly the RCE plates lower my front an additional 8mm w/o penalty to bump stroke- added to the 22mm the springs lower- it gives me 30mm of lowering
In the front, front droop is 104mm (oe WRX is 93mm), bump travel is 66mm (oe WRX is 70mm)- not too bad considering the ride height is a full 30mm lower than stock
Thaks to ericd for these pics- which really illustrate exactly what I'm getting at. He assembled a strut w/o the springs, but included the bump stop. He then moved the suspension through several ride heights, oe then 20mm lower, then 30mm lower. Mind you these are Koni's, so the oe strut would be slightly worse off yet. You can clearly see that at 35mm lower it's well into the stop already- at rest.
oe height
20mm lower
35mm lower
I've got a few bump stops from Ground Control that I'm going to play w/- both are slightly shorter than the oe stops.