Right sorry to sound think and stuff and i have done plenty of searching now not come up with that many answers,,, i'm not a boy racer but i do like a nice sound to my car and fancy a bit of an exhaust but not something too obtrusive, also i fancy a blow off valve as had many many turbo cars and bikes but do the t5s work ok with an atmospheric type bov as the last car i had was a passat 1.8t and they just didn't like anything other than a recurculating one,,, also air filter? etc etc lol