Tim,
Hoosier VRLs are normally 335 x 30 x 18 rear, 305 x 30 x 18 fronts.
These rears are quite a bit shorter than the 345s that come with the car like more than an inch overall.
Short answer is yes, you will want to lower the rear of the car and the front too. I'd recommend you call Archer Racing and check their specs for this tire set up. Ask for Russ.
I sometimes run a similar set up (heightwise) with the Hoosier R6's, i.e. 315 x 30 x 18 fronts, 335 x 30 x 18 rears. Try to keep a minimum 1/2 inch rake front to rear (rear higher).
Those of us that have tried the VRL's and the R6's tend to prefer the R6's for durability and they are both the same rubber compound though have different construction.
On the Forgelines, I'm guessing you went 11 x 18 fronts, 13 x 18 rears. If so, check your offsets to be certain that you don't rub when turning (brake lines up front at full lock), fenders and fender liners at the rear if too low. Not all Forgelines work well on SRT-10s.
Good luck,
Dan
