Ordered this truck the first year they offered the 6.5TD. Am planning on putting on a free flowing exhaust and would like some input on which is best. Also, have decided that propane injection will give me the best bang for the buck and have found that Bullydog and the Powershot 2000 are the only ones out there that offer this add-on. True? Any major difference between the two that would warrant one over the other?