Less than 20 quid on TFSI tuning for titanium studs and nuts
Someone on the tfsi tuning page was selling a kit like this
Just remember that if you do this you have to remove ALL pipes off the HPFP to remove it. You won't be able to leave the rubber hose connect as you can with normal bolts.
Here is a link to the bloke who makes them, he hasn't got any listed on eBay but is a way to make contact him with him maybehttp://www.ebay.co.uk/itm/Vw-Audi-Hpfp-Screws-Titanium-/161922544433?hash=item25b355f331:g:oPAAAOSwFGNWTLzj