Mac offroad h pipe, problem!!!

First off, the smog pump isn't hurting anything. Doesn't do much good either, but it it isn't the parasitic monster that many make it out to be. If you aren't going to have it hooked up, you will have to plug the little pipe on the H pipe that is supposed to go to it or you'll have a leak there. At least, my MAC offroad pipe still had a little pipe for it. Second, I don't think you have exhaust manifolds. You should have shorty headers, and the beauty of the MAC pipes is the ball and socket type flange arrangment which makes bolting them up without leaks much easier. If you have a leak you'll feel it with your hand around the joint, and if the car is cold you may even see the exhaust. It should be quite a bit louder than the factory pipe with cats, and if you have a stock 5.0 it may cost you some torque, or even a lot of it. Or, none at all- everybody seems to have different experience with these. Do a MAF, TB, RR's, pullies and gears and then see how it feels. Regardless, if you think you have a leak then you'll want to find it and fix it ASAP, you don't want the joint to get too seated that way if it's wrong, it'll just make it harder to keep it tight later. Good luck