How about a BMW M4? Twin turbo but now has a pretty good stock exhaust. Would you update the downpipes ? I've Dinan tune on it so it's got better boost. I am just worried about it going into limp method. DC – I don’t suggest a brand name – https://holdenbfjlp.buscawiki.com/921161/how_much_you_need_to_expect_you_ll_pay_for_a_good_gle_63_downpipes