my ktec decats has made the car very raspy, but if you take it easy (increase revs slowly) around town it is not really that bad.
when you blimp the throttle or floor it suddenly thats when the rasping starts, i save that for use in non built up areas such as country roads. doing this in built up areas will probably get you loads of attention and someone phoning the police and reporting you.
it is quite handy actually to annoy someone you dislike, just sit outside their house and keep blimping the throttle! (i haven't done that as i have no enemys! yet, anyway...)