Maybe you should have read up on this first bud You cant do many mods to these cars unless tunned now that you have a full exhaust and driving without a tune you risk running Overboost and bye bye motor hence why the engine light came on And yes 5g should get you what you want depending on who does the install and tune Injectors,intercooler and intake fuel pump x3 and tune may go over 5g And a port and bigger flap for the gate is a must to control boost levels