Aside from the 500whp claim being a bit high for an 18k with 1050 injectors being a bit of a stretch, it looks like a solid build sheet. I'd want to drive it and make sure the drivetrain isn't making any untoward noises and get a compression test on the engine before considering the car. Being an 08, that's a high price in the current market and mods don't add value unless you would spend the money anyway. It also won't help you if you have to finance.