There are both kits out there. Toyomoto, PFS (Peter Farrell Supercars) and Turbo East all had them when the car first came out. Everyone was using Greddy E-Mange for the fuel maps. The kits are LOUD and whinenie.
I would say go with a stage 1 or 2 Turbo Kit from PFS. Ray really has his stuff together there. You can google them.
You wallet and the sky is the limit with the Turbo. My buddy has a GT35R on his 2004 IS300 and has over 600RWHP. His car has been done by PFS. Much more than your probably looking to do though.
I did an install of a Turbo East stage 1 kit with a piggieback ecu and we always had heat issues. Do it once and do it right. Just my two cents.