Mmm interesting read for a Thursday morning Well done on the write up, you've pretty much covered all corners (I think).
Anyways, here are a few of my own opinions; I also have a R34GTT auto, only it's the coupe version.
1) The R34GTT is a vast upgrade over the R33GTST; everything from engine to suspension to interior/exterior trim has been upgraded. It would be false to say that there is close to nothing between the two cars. Saying that, the RB25DET in the R33 is a NOT the same as the NEO RB25DET. You will find that once you begin to mod, a lot of the standard things you can do to the non-NEO will not work on the NEO engine.
2) The auto box with tip-tronic selector is a great way to a) get more power quickly, b) have a bit more control over the car and c) have more fun. Even in its stock form, the tip-tronic gearbox is very responsive provided that the ECU does not "prevent" you from changing gears.
Believe me, there has been many times when the ECU has just stood up and said NO to a up shift or down shift. However, this can be sorted with only a few simple modifications.
3) When you guys say that the tip-tronic gearbox gives you better acceleration etc etc. I used to believe this too but have come to discover that simply planting it in D gives a better result. If you don't believe me, feel free to try it out.
The one thing you will notice is that your boost will not drop off with each gear change, and you will be able to take your car to redline before it automatically shifts (don't be scared that you'll just bounce off rev-limiter) it will shift!
Anyhow, I'm sure you'll all come to your own conclusions about the auto in due course - it's been a very fast and steep learning curve for me personally. So many things you can do, so many things you can't do which adds to the challenge and learning experience in my opinion.
It'll be interesting to hear what some of your end-goals are for your cars - mine is to build a 300rwkw street-response machine. It will mean that it will be average on the track but unstoppable on the street which is OK as that is where I am most of the time.
S