Keep it simple:breckiam said:Something that I can DD and not have my engine blow up on me
A good custom tune
Quality gauges to monitor (Defi for analog, AEM for digital)
A good S2 tune should have no real impact on reliability (e.g., if the car blows up, it's likely it would've done so stock). Boost / WBO2 gauges will help you monitor everything is in line; EGT / Oil Temp / Oil Pressure would be three more I would recommend if you'd like a broader picture.