I have had no problems with my standard shocks and new lowered springs (whiteline). If you are going to change both you would be better off buying a set of coilovers which have been matched and will just bolt right in.
The drop is totally adjustable - price around $2000 and up in OZ (would be cheaper in US). A few out there: Try http://www.3gwrx.com/forum/index.php?topic=658.0 from this site for a start. Unless you are going to track it, just new springs are way cheaper and all that
is needed by most people.
Another way to do this if you don't want to mar up the shaft of the shock itself by using vice grips:
Get your socket (17mm for the fronts, 14mm for the rear IIRC) and a grinding wheel. Grind off some material from either side of the socket to make the two sides flat so you can fit an open ended wrench onto it.
Basically it's a DIY, poor-man's pass-through socket.
Using the socket & wrench and an allen key passing through the middle of the socket, you can tighten down the strut top. It's helpful to have two people to do this however; one to hold the strut assembly and one to torque down the nut.