alright, I'm not an expert at tuning, but there are some things I feel I should point out in this thread.
1. For that price, you can't go wrong. I would get it. Even if you don't use it, you can sell it to make your money back and then some.
2. Your gains depend solely on the mods you have done and the tuning.
3. Street tuning IS NOT crap as expressed above. Generally, the best way to get it properly tuned and minimize your costs at the dyno shop is to street tune it the best you can BEFORE making an appointment for a dyno shop. Then dyno tune it. Then after it's dyno tuned, do some serious datalogging while driving in real world conditions and "fine tune" it for your driving style and real world driving conditions by street tuning it one more time. Dyno tuning is great for getting accurate numbers and data, but that's on a machine while the car is not actually moving. It can't take into consideration the minor changes that occur from driving in real world conditions.
4. There really is no such thing as narrowband tuning to begin with. It's so inaccurate that you don't want to base your tuning off of its readings. You have to have a wideband to tune properly so there shouldn't even be a discussion about using a narrowband anyways.
5. The best thing you can do is to start reading about tuning, and when you're completely exhausted from reading about tuning, read some more. Knowledge is the first step, then applying that knowledge to gain experience is the second step. You can tune it yourself (which I always encourage), but you need to be smart about it and don't do dumb shit (like drive it super rich for a month even though you know better and then next thing you know you have washed rings and wore out rod bearings :roll: :retard
That's all I'll add to this right now. Good luck!