I have been reading these forum postings for two weeks. Two questions...If I delete DPF and EGR, add an air intake and mini max, should I go with 4 inch or 5 inch exhaust. I want this thing to sound impressive without robbing efficiency. I saw a few posts where they claim the 5 inch exhaust will rob some of the performance, but the stock system is close to 4 inch. When I pull up to a light, I want this thing to be noticed....suggestions?