Astraeus,

As someone who is running three Tamiya tanks, I think you have the right idea. If you end up really liking tanks, you can always upgrade. If you don't, your not out a lot of money. I have a Panzer III Smoke & Sound (S&S) on order. From posts on the forum the smoking units seem to be a lot of trouble, but the upgraded tanks come with sound and a better speed controller. For info about the Airsoft gun you can search past posts. From what I read and heard the one thing that HAS to be replaced is the Rear Idler Wheel - they just don't hold up. All the suspension and track upgrades can wait till after you've had a chance to drive a bit. We have a club that battles tanks using the Tamiya inferred system. A couple of members have converted Panzer III's, and are basically happy. They get the track pins to stay in place with a drop of super glue. Neither is running metal tracks.

Good luck