I have the RC 10 GT and my buddy has the XXX-NT. I moved the battery in mine up to where the receiver is supposed to be, and his battery is in the box where it is supposed to be. While there is considerable difference between the trucks just in design, I have them both in my garage, and I have them both set up for my track behind the house. I had a tough time with push, and wheelies until I moved my battery, and that helped LOTS. As stated before, it tends to loosen the rear end up, but not to a fault(IMO).

The losi doesn't have the push issue, but it seems to exhibit nose up characteristics, and requires more mid-air input to set down nicely. I am still dialing in for the jumps and the surface. I tend to groom the track often, so it is generally a smooth surface, not all rutted up and rough. And I don't drive the losi as much, just for initial testing of whatever I just changed. I have to wait for his input to try and set it up for his driving style, so it has taken quite a while to verify changes as improvement or not.
But overall I think the losi could benefit from moving the pack foreward, but my buddy is reluctant to do that until he gets a replacement for the stock steering servo.

So...What all that rambling is meant to convey, is that you should set your truck up the best way you can for your style of driving. If it means moving stuff around to 'balance' the weight distribution, and center of gravity, then try it....If that doesn't work, try something else.
Have fun with it, and let it consume all consciousness(ok to stop and eat once in a while tho).
Then go to the 'you know you're addicted to your stadium truck when...' thread and tell all about it.

Long post...raining[&o]...wanna play