I have the single belt stage 1. What are the advantages of the dual belt going to be? I know you can get a smaller pulley for the single belt from brenspeed. It takes the crank horsepower to 560.
A few things I can tell you about having the roush tvs. Once installed you will have to remove your pcm from the car and send it to roush for calibration.(there is an additional 100 dollar fee) when you get the calibration from roush you are going to be running pig rich. You will also be leaving lots of horsepower on the table due to the rich condition.
I chose to forego the roush tune. Instead I had it dyno tuned so that the car would actually be running good rather than rich or lean from basically a mail order tune. Of course you need a sct tuner or Diablo to have it tuned. You can usually get one used.
The stage 1 kit made 452rwhp STD a corrected and 416TQ.
I have been contemplating the brenspeed 560 pulley. Of course I need to upgrade to the gt500 fuel pumps. After talking with brenspeed they feel that their 3.5 pulley is as small of a pulley they feel comfortable putting on a car. The stage 2 kit from roush comes with the gt500 fuel pumps.
450-500rwhp with a good tune is the absolute max you can make with stock internals.
The rods are the weakest link in the engine.
You can run more than that at your own risk basically.
Make sure your shop is familiar with the 3v. I have seen a lot of stories where guys take their car to a shop to have work done, then they lose the engine because of a bad tune.
Also don't be surprised if your shop suggests whatever blower is easiest to install. Lol
You may find the below link useful. Hope this gives you some insight.
Tvs 2300/ 452rwhp 416rwtq