which springs
 

give the biggest drop on a Bugeye WRX with standard shocks

Tein S springs are about 30-40mm but that's as low as you want to go - in fact many will advocate dropping less than that, only 20mm or so really to retain ride comfort.

A 40mm drop may not be the best for your handling, and you might find your shocks don't like it and fail shortly afterwards too.

coilovers if you want that kind of drop, right I'd better do some saving