Okay buy a Mustang GT because the game doesn't have a GT500. Go to a 'One Stop Shop' and get the following upgrades:

Parts:
Body kit: Body 1
Spoiler: Stock
Hoods: Stock
Rims: BBS GT
Roof Scoop: Stock

Performance:
Whatever you want!

Visual:
Colour: 44/80 (RED)
Vinyls: Strips, Stipe 1
Vinyl colour: 1, 1/80, 2, 1/80
The rest is Stock...