I don't think so. As far as brake upgrades go, the most I know of people doing here are stainless steel brake lines and after market drilled/slotted rotors.
How big do you plan on going? I am running 265 BFG M/Ts and I did not change my brake lines. However I do have R1 Rotors and stock pads.
I think the shop is just trying to get some money out of you. Don't listen to them. You've come to the right place for good answers. Let us know this:
1) How big do you want to go?
2) Does your VX have any sort of lift?
Bart