If he's indeed all stock I wouldn't even bother upping your shot. Honestly the best way to shut people like that up is to throw down a $100 bill and tell him that if he's that sure of his ride to match it because tires aren't cheap and neither is your time. Winner keeps the $200. Better if its in front of his friends so if he *****es out they all see it. If he actually does match it then you make $100 lol. Or he's sandbagging it and has some kind of crazy setup he's not telling you about.
2000 Mustang GT Steeda build #48. Bolt ons, suspension, Novi 2000.
Just because I give you advice, doesn't mean I know more than you. Its just means I've done more stupid ****.