Z's don't have an over heating problem per se, but any turbo car need special attention payed to temp, coolant, oil, etc. A faint gas smell at start up is normal, but if it lingers it's prolly a fuel line. Stock boost on a TT is ~9.5PSI, 7PSI is safety boost. Do search for mods and hourse power, but stage 3 = mucho funo!