Shorties really aren't worth the money. You may see slight gains in power, but mostly, it'll just be a little better sound. Long tubes are the way to go. You'll definately see gains in horsepower and torque, as well as improved throttle response. After seeing the difference in dyno numbers on my buddy's silverado, I won't even consider shorties as a mod. On his truck, (02 Silverado RCSB) long tubes gained 20 horses, and 30 lb/ft of torque over the shorties. The shorties only gained about 5 horse and 10 lb/ft over the stock manifolds, and you can get gains like that from porting the stockers.