what mods to an 04 civic EX

Daily driver and keep the warranty intact is my goal. I just want a fun car to drive that gets good gas mileage. The vehicle I'm leaving behind is an 11 second setup which will be missed, but 50 dollar fillups every 5 or 6 days won't. I can tell you what every single mod did for my large displacement v8, including the supercharger. The long tube headers and ported heads were necessary to run the 20lbs of boost I'm running. The motor was built, of course, with forged internals and such.

I guess I should have narrowed down the questions and provided a bit more background.

Ford has become a warranty nazi. They will void your warranty for even an aftermarket air intake.

My questions really center around what is the best bang for the buck that I can get by the honda dealership in the event that I need warranty work. If the answer is none, then I'll leave it stock.

I'm not new to horsepower, but I am new to horsepower with something that has half the cylinders and 1/3 the displacement.

I was just looking for some answers as to what has worked for folks.

I don't want my car to sound like it has a bad exhaust leak running down the freeway. My current vehicle can be heard FAR, FAR away and I'm looking forward to some peace and quiet...