Really depends on what look and performance you are going for. The sportlines are pretty extreame drop and aftermarket shocks/struts are a must not to mention c/c plates if you dont want to run through tires quickly. I'm not sure what the spring rates on the two springs are but im pretty sure the sportlines are stiffer then the prokit which is better for auto-x or open track and will also slam or tuck your wheels in most cases. With the prokit though you wont get as much of a drop as with the sportlines so if you can deal with a little bit of wheel gap then id say prokit unless you really are going to takethe car racing. With the sportlines you may have some clearence(sp) issues with the wheels unless you roll your fenders or possiable some rubbing with your control arms or sway bars at least thats what happened with my car.