Hmmm, I guess you mean adjustable springs when you say "coilovers", right? Real coilovers cost $800 and waaay higher. If you're talking about Ground Control or Skunk2 adjustable springs, you're better off not getting them. They can have a very harsh ride, and will probably kill your stock struts with just their spring rates (highest out there for just a spring). You'd need something like Koni Yellows or maybe KYB AGXs to control them.
You're better off getting Tein S-Tech or C-One springs (both 1.4", as close as you can get to 1.5"). If you're willing to sacrifice a bit of height, you can also get H&R (1.3"), TRD (1.25"), or Eibach Pro Kit (1.2"F/ 1.1"R).
Technically our stock suspension is a coilover design. But blue is right here; you don't need to go overkill with your suspension. It will cost you mucho dinero and you will likely hate the ride and never explore the limits anyway. Get something basic, and proven.