Wow! I've not been on the computer for a week or so and just now caught up this thread. Thank You for all of your replies, I very much appreciate it! Lots to think about but also made me feel bold enough to try a LiPO in the Taigen and it does work. The Bulldog will be my test bed for mods and other non factory things, adding a fuse as crius suggests and a low voltage alarm / cut off would fit that bill but at the same time a 5000mah nimh battery is cheap and easy...
Tankhobby, I know exactly what you mean as I am the reverse, I'm just now emerging from my getting married and raising a family window. I'm finally able to spend time and money playing with the RC tanks that were so cool that I saw 20 years ago.