Follow that thread...depends where you get it...probably between 170 and 200 bucks depending on whether its a big outfit like Summit or your local speedshop.
not until I throw a pulley and throttle body on, then I will take it to the dyno. If you do a search, a few people have posted dyno results published in the CAI shootout in fast fords magazine. For the article, they used the 01 system on the 03, it fits but not very well. The filter is the same for both systems, it just the heat sheild that has been slightly modified, so the dyno results should stay the same. It had the highest rating on a stock cobra, and was in the top three for the modified cars.