I plan on taking my Viper to the dyno once I run through a tankfull of Sunoco 94 octane so the PCM will have learned how to drive it with the Roe Racing VEC2 and the 94 octane VEC2 card programmed into it. I will be checking for air/fuel mixture as well as HP & Torque. I expect to get around 575 rear wheel HP and 600 pounds/feet torque. All is dependent at this point on the Snow Gods - I got the 94 octane and 100 octane computer cards for my VEC2 a week ago and haven't been able to drive it since...and the forecast for the next week looks like my Viper will be Queen of the Garage for another week...
VIPER GTS and my Viper were being worked on in that order by our Viper Tech, putting in the VEC2. We both have 3" Corsa cat backs and I think we both have high flow cats, though they may be from different manufactures. He has B&B headers and I have Belangers. Both our cars sound meaner than feces at idle and at part throttle, but his is higher pitched than mine. I haven't heard his at full throttle and I've only heard my Viper at full throttle while inside it. I haven't been in Viper GTS's to say how it sounds inside the car. His car was going through more of a learning process with his PCM than mine and this was when his car was first road tested by our Viper tech, the final sounds may be slightly different now. Sean's a dealer for B&B headers, but both B&B, Belanger, and one or two other brands are supposed to be good. Just make sure they are coated like Belanger headers are, either by the manufacture or by an aftermarket coater. coating really helps hold the side sill temperatures down as well as temperatures in the engine compartment where delicate electronic devices don't like heat, like your PCM. My underhood temps are not bad even after frolicking fairly hard. You will get more power with 1 3/4" tube headers over 1 5/8" tube headers.
The Roe Supercharger made my exhaust system quite a bit quieter and changed the quality of the sound as well. It was sounding like barely muffled open headers on a built big block before the superchager and now it sound like a monster exotic extremely high HP engine. Inside it is quiet enough now to even think about reading the instruction manual and setting radio stations, but I haven't. It's still pretty loud by 99% of the rest of the cars on the road standards, but I don't worry about getting an anti-noise ticket like I used to.
Other things - you'll need new spark plug wires to get the spark to the inside of the cylinder - I got Magnacore 8.5 mm at JonB of Parts Rack's advisement and they work perfect and I have no radio interference that i would have had with Mopar Performance Viper wires. Also, a 180 degree thermostat will help - I also got Roe radiator hoses at the same time. The Roe fan controler and timer also helps keeps things happy in the cooling system after a hard day of frolicking.
I didn't do 1.7 roller rockers because I wanted to make sure everything was working perfectly with the Roe Supercharger - this was before the VEC2 and some people were having engine management problems (detonation) - and also I had overspent my budget. The VEC2 appears to have solved any & all problems with detonation, but I want to get an air/fuel check done on the dyno to make sure everything is running as good as I'm sure it is. I may be satisfied with the power and not add any more mods to it or I may add 1.7 roller rockers next year. It looks like 1.7 rollers will add quite a bit of torque & HP at 2,000 -3,000 RPM, which is where I normally drive & frolic at. I got the Roe Supercharger because of the torque at the lower RPMs because that is where I drive, not near red line, though the 1.7 rollers do add quite a bit of power near the redline (6,000 RPM) over stock rockers, for those cases of extreme frolicking. Actually, on a HP per dollar basis with the Roe Supercharger, the gain with 1.7 rollers is a good inexpensive mod. But, do I even need more power with what I already have?