Getting my exhaust redone and dumping my flowmaster tomorrow and need to know what is a good magnaflow to go with? They have so many options. I am getting 3" in and dual 2.5" out but I have found two main options through magnaflow...the standard aluminized #12588 and the XL13288. Which one of these would work/sound best on my 87 350 w/thorleys. I dont want loud, but I want the best flow possible.