Since you have a s/C you are correct, you dont want much back pressure. A lot of people including me run a single in dual out muffler to Y their exhaust into duals. You can run true duals if you want dut the power difference on your motor will not be much different than a good Y setup nd be les expensive to fab. Magnaflow is good stuff, they are my second choice after my mufflers so i think you will be pleased. Let us know how it turns out.