Put a race pipe or gutted cat in place of the stock cat in an srt-4 and you will get that sound. Take the baffle out as well and it will be even more noticable. I had 3 inch turbo back straight thru on my old one and you could hear it like it was open dp. An srt-4 turbo is small also, so just going thru a parking lot it will somewhat spool thats why you hear the sound but without the loud rush of air when you hit boost. On bigger turbo'd cars it doesnt do it at lower speeds like in a parking lot