Need some help

I have an '04 Grand Prix GT 3.8L V6 3800 Series III. And I want to make my car faster but I don't know that much about tuning my car.

I wanted to get a K&N Performance Intake Kit=16.78 HP @ 5248 RPM for $356.79. Is it worth buying or is there something better that I can get???

Air system will make it breath better, but until you can control fuel injection and ignition timing, you only stand to gain about 5 horses. I would also check into a performance chip for the computer to take care of those issues. A cooler thermostat will help a little also. You have to trick the mind of the computer to your way of thinking!!!

performance chip??? would allow my car to go 140mph since right now it can only go 110mph...I don't know why it just stops there even tho it says it can go 140mph

Key words here are "says it can". They can create any given circumstances while engineering their products. Under "THE BEST CONDITIONS" they say it can. They have no control over the condition of your vehicle. Kind of like putting high speed rated tires on a YUGO with 200,000 mile on it. You can't get there from here. Sometimes you just get what you get. They should say " up to and including 140 mph depending on your vehicles condition". Wouldn't be good salesmanship to limit your products capability.

Speedos on high performance cars read about 10% to 15% higher speed than they are capable of.