Check the spark plugs! Make sure they are not broken or fouled out. Also, check to see if it has the updated, blue or green, fuel pump relay installed.

 

I would pass on a car with so many miles and mods man, it's just not worth the possible catastrophe in a few months if the car was poorly tuned or even worse, flashed back to stock and still running the mods it has. Just be patient, keep saving, and you'll find a lower mileage one and hopefully it is completely bone stock.