2.2L turbo is the max for weight limits on a super, anything bigger cant be legally approved unfortunately, and if its a beam bug it will be lighter so even less capacity allowed unfortunately.

best bet is talking to this guy...
http://modplate.com.au/ 
or this guy for a vw specific...
http://vwpartsshed.com.au/ 
both have been helpful to me

So build a 2.2