Vtec Engine
 

If I have a 1999 2.2 Vtec engine and the only thing that the engine is running is the alternator---plus there is a performance intake, headers and an oil cooler,will I see any increase in performance and/or gas mileage?

Thanks.

Some performance gain, porb not much.

Gas mileage, I don't think that will increase.

Tuning
 

What does a "Street Tune" consist of?

Thank you.

I don't think you can do a simple tune to the car since it's OBDII, Also for just only the header and intake you can get away without tunning, but you might not see the full "gain" in hp, mine 99 with intake and full aftermarket exhaust without tuned still did good on dyno, and the A/F is good all the way to red line without wide band controller.

a street tune is where the tuner rides in the car with you and adjusts your Air Fuel ratio to your driving habits. When having a intake and exhaust on stock ecu you end up running rich (that why you see hondas with big black spots on the bumper where their muffler comes out) At the point you can save a little bit of gas mileage b/c your tuner can tune you not to run rich and run a good a/f ratio. Like Piggylover said your OBD2 so you might have to spend a little bit more money to get any type of tune. You would have to buy a chipped ecu and a obd1-obd2 conversion harness.
The OBD2 ecus might compensate better than the obd1 systems will. I'v always used OBD1 so I will have to take Piggylovers word for it.

Thanks a lot. I am learning...However there are words and terms that I will have to look up in order to get the full meaning.

So it sounds like just doing the simple mods that I described , leaving the engine stock is the way to go.

Thanks again for the help.