Dump valve/waste gate / flutter

Hi everyone I'm new to this a complete novice. I own a octavia mrk1 vrs 180bhp now this may sound stupid but I love the sound of the dump valve if that's what it is it makes the tssshhh noise lol now heard some that are loud on a mrk1 iv even heard some that make a flutter noise my question is how do I make it louder or how do I get it to flutter and what would I need with out losing any power? It's is standard vrs it has not been mapped how ever I am looking to have a stage1 remap in the future. Hope anyone can help many thanks