yeh every turbo has a wastegate wether internal or externally run
and yeh sr20s run bovs but the return is to small so it flutters
compressor surge is bad, normally when the front compressor cover not matched correctly with the exhaust housing
a lot of hi-flows (even gcg were having problems on there skylines hi-flowed turbos)
when coming/on boost they would get jolty and hesitate
compared to mad flutterz where you either run no bov from factory or block it off
where the compressed air can't escape from the system (bov will release) they will get pushed back into the compressor blades of the turbo
that then makes the loud chopping noise - aka tssuuu tsuu tsuu
not benifical on a street car, besides the look at me ima sick kent noise factor
on a track car it actually helps keep the turbos pressure up so in fact lessens the lag
however it still limits the life of the turbo to what it could be
my car running a garrett hiflow, and through a gtr bov on 19psi still flutters when ive got a pod on
but I'm not a fan and try to keep car legal so i keep my airbox on