Contact compressor racing, they usually have some sort of holset in stock.

They had some hy35s on ebay last week.

Only problem with fitting to a cossie is that most are external wastegate.

Hx35s are good for 600bhp.

More info the hy35s here

http://www.driftworks.com/forum/part...-2-3-days.html

http://www.ebay.co.uk/itm/100-NEW-GE...p2047675.l2557