I have a hopped original T-Maxx, and I just bought the Savage. So far, I like what I see of the Savage. Other than a few pain in the ass design flaws, this thing looks like it will kick some tail.
I have put my T-Maxx up against Pirata's Savage, and it held its own. I think both trucks are great for what I do, mudding, jumping, bashing, etc. When I get the Savage's engine broken in, I'll let you all know what I think about what it can do.
As for selling your Maxx to get a Savage, if that is the only way you can get a Savage go for it. Just think about what you want to do, though. If you sell it on eBay or any where else, there is no chance that you will get anywhere near what you put into it. Soooo...I'd suggest saving the T-Maxx and your money...then when you have enough money, you can buy a Savage. You will then have two awesome trucks to play with.