im gonna give a logical answer and this is if you are set on a garrett, gt40r, the gt35r is not gonna be a "650ish" turbo for that setup EFFICIENTLY, its rated for 400-600hp. Acts of god will make that turbo shine any higher than 600. You wont make higher than 700 with a gt40r efficiently, but if you want 650 or a little more youll want the gt40r OR the gt4094r. Both are not really that much more than the gt35r and are just as nice. if you get the gt40r or gt4094r, your injectors will max out before you max the turbo out.