Will Performance Upgrades = decreased Reliability?

actually many upgrades will improve reliability because the aftermarket products are made and designed better. First you will notice a huge gain from a cold air intake. If you live in a rainy place you might want to go warm air or take off the bottom pipe to save the worries. things such as the sct or sct computer upgrade will also give better performance while making the engine run much better. I am sure you will get many responses on this, but there are a lot of mods that will improve the car.

I live in San Diego, so Cold Air Intake would be a good first upgrade? Do you know of any places near my area that will install one?

(I would do it myself if the installation is fairly simple)

Also, would it void the cars warranty?

A cold-air intake is probably the most gain you can get for a Duratec for under $200. As long as you don't try to drive through several inches of water, you're not likely to have any problems with it. Most any speed shop / tuner shop can install one, a place near me wanted $50 for it.

Your warranty is fuzzy. It can't be voided entirely by a part like this, but part of it will be. If you come in with a blown rear shock absorber and a CAI installed, your warranty is fine. If your engine seizes from ingesting dirt or water and you have a CAI installed, you're out of luck.

it is really easy to install. the difficult part is getting the stock intake out. it isn't hard just takes time to get to all of the screws in weird spots

^^ I second that..

I am new to working on car myself. I was down there installing clear corners.. and it is time consuming and frustrating, but with some patience and bacis set of tools (think scredriver and a wrench) you will be fine... just take your time and use good judgement...

Igor