Where you at, there is a place on Heathcoate Rd, Moorebank that does them, alot of garages do, just cruise you local shops would be the easiest I recon, They advertise it on there ads and signage, look for imports or Hi Po cars in them.
As long as you do it right and tick all the saftey boxes you shouldnt have problems, plumb back your BOV, tune it for emmisions, have a good Cat and make sure it isnt to loud.