Dualling cars

YOUR warranty will be voided with respect to any modification you make to your car. You're making a modification that is taking it away from the specification as it was sold to you, so you have to carry the responsibility for those modifications. With LPG systems you need to talk to the installer to find out what cover they provide. The price you've been quoted does seem a little high, I would think $3500 is about the right price for a sequential gas injection system for your car, which is what you should fit. If you do, you shouldn't experience any problems with the Gen III V8.