Welcome Brian...
I'm also a big fan of R/C Tanks and have build them all so far... Well almost, my Leo is about 90% done. It's been to hot out to finish it.
If you are looking for upgrades, check out BackYardArmor.com. They have a lot of upgrades parts for all of Tamiya's R/C Tanks.
Back Yard Armor They have a accurate suspension upgrade as well as a realistic main run recoil upgrade. I added the recoil upgrade to my Tiger and it's well worth the money.
Now if you really want something special. They also have a SturmTiger Upgrade. As soon as I can convience the wife that I will die without it, I'm going to order it.
Good luck and have a lot of fun building it.
Pat