I just bought a talon tsi and would like to start upgrading it. what would be the best first thing to buy. Im considering either performance exhaust or a blow off valve. Which would add more power?  

Congradulations. First off, your definetly going to want to do some reading up. The 4G63 engine is one of the baddest four cylinder engines ever made, but as forgiving as it is, you are going to want to do a few things before you start throwing aftermarket parts on it.

First off, pay a visit to www.dsmtuners.com . Read their upgrade path, newbie common misconseptions, and engine primer. There is alot of good info there, and also you are going to want to visit what I like to refer to as the dsm "bible", the "VFAQ" often. It's www.vfaq.com , so start reading.

In short, first off, before you do anything, you want to make sure the car is in good running condition. If you have no idea when the timing belt was changed last, assume that it is old, and overdue for a change. If it snaps, your going to be in for costly repairs. A tune up, and boost leak check  among other basic stuff should be performed. Exactly how to peform all of these maintinence tasks yourself can be read on DSM Tuners or the VFAQ.

You have a 2nd gen, so that means that you have the gay plastic BOV, apposed to the 1g's metal one, which is an excellent design. Adding a BOV won't give you any benifits towards performance at this point, but if you want to get it out of the way first, I would suggest finding a used 1st gen  BOV, they are pretty cheap ( usualy around $30) and easy to find.

An exahust is going to yeild significant gains, and I would probably reccomend it as a first modification, after all your maintinence has been performed. I and most people run 3" turbo back exhausts, mine is pretty much an RNR 3" downpiipe with a custom fabbed 3" catless exhast.  

thanks for the advice. as far as i know the car is in pretty good condition. The belts look new and the car only has 50,000 miles on it and it is ten years old. I think my cv joints are broken do you have any advice on where to get new one and how much it will cost?  

The belt that I'm talking about that is important is the timing belt, the belt that is driven off the crank and turns the oil pump and cam gears. If that belt is to break, being that the engine is an interference engine, you will at the very least have bent valves, and be taking the cylinder head off the engine. The timing belt is under the timing cover, you can't see it unless you take it off, which requires the removal of some of the accessory belts and their pulleys. And there is no telling if it is ok by looking at it and seeing that it looks "alright", the best thing to do is to change it.

You can get CV axles from Advance Auto Parts or the like for alot cheaper than the dealer, one side is like $85, the other is around $100 I believe.  

i have a very strong feeling that if the car has only 50K on it, the timing belt has never been changed.  get it done first thing.  i would replace the rolling tensioners while you are in there as well.