Scorpion is very popular and no fitment issues. There are a lot available so its down to budget really.
Japspeed K1
[youtube]http://www.youtube.com/watch?v=su2J_COwzF8[/youtube]
Japspeed K2
[youtube]http://www.youtube.com/watch?v=OlzPxYUE5-w[/youtube]
The K1 is very loud but the K2 is a little more like OEM.
There are a lot of other options such as the Nismo but they are a little pricey nowadays.
If you can get up to Zedfest thete will pretty much be every variation on show. I am not a big fan of youtube samples, very difficult to decide from them.