Air suspension or turbo kit?

Which should I invest my money on first for my 2014 Honda Civic si coupe? This is going to be my first mod on my car but I can't decide which I should choose first

If you turbocharge it you can say goodbye to the vast majority of your warranty. Anything related to the engine or transmission would no longer be covered. As for air suspension - what are you looking to gain there? The Si suspension is very well sorted, you aren't going to improve it by replacing the stock suspension. Note that will also invalidate any portion of you factory warranty that is impacted by those components.

In short - both or your mod ideas will cost you a significant amount of money and will undoubtedly lower the value of the car. Stick to cosmetic mods - maybe some nice custom wheels or something (but don't overdo the size) that won't cost you any warranty coverage.

Where do you even come up with these stupid ideas? You might as well wait until the warranty is over before doing anything. And even if you want to modify, a performance K engine is a high compression engine designed for making high peak naturally aspirated hp, not hp through boost. If you want to modify your engine, do some basic bolt ons like cam, exhaust and headers. When combined with a tune people on the forums say this should net you 40 hp. As for suspension, what are trying to do? The stock suspension and the whole car in general is already tuned from the factory to make the best possible compromise for overall performance around a circuit.