Both are performance mods. Your getting more air in and letting gases out with less resistance. You cannot let more air in without adding fuel and expect A: drivabilty to be maintained (it'll SUCK!) and B: gain any performance.
If you plan on doing those mods, at the very least get a Race ECM or tune the stock ECM. ECM Spy is free and so is Tuner Pro, you just need to make or buy a cable. SEARCH, this has been beaten to death.
The Jardine on a XB9 with K&N result in pretty significant gains when tuned for them.
~Mike....
