I would go with the comps "thumper" series, call them and talk to a tech and tell them your combo. Also know that the exhaust system has a big effect on sound too, you may want to go with long tubes and not knowing what kind of flowmasters you have, you may look into the super 44 series (single chamber) and your X-pipe is great but H-pipes sounds better at idle (this mis my opinion). And not knowing what your friend has, he may have a carbed set-up and sometimes when a car isnt tuned perfect, it makes the cam sound bigger.