sully- you're likely to see and feel the same increase with RC tuning... So... be prepared to fall in love AGAIN with your car. As far as the balancing goes, ehh, you'll hear both sides of the camp on that. If you car is running good, you can check with VCDS (I forget which channel) but I think it's the quantity injected values or something like that at idle. As long as they're close to each other, your more than likely good to go. Lots and lots and lots (I don't think I can overestimate that) of people run nozzles that aren't balanced with excellent results.
However, some people have bad results after installing nozzles and get them balanced and it's great. If you were building a 200hp plus TDI and were running race nozzles and high states of tune, I'd definitely recommend balancing. On a stock, old, engine I say it's up to you. Wanna spend another $100 for peace of mind? Your call my friend...
I say put that $100 towards your replacement clutch. The one you'll need soon after you get remapped at the GTG LOL!!! Happy modding.
--edit-- Drivbiwire does them also. Lightening quick turn around and top shelf customer service.