Yes, the Xray is a little heavier than other cars. I see from the pics that you have a bolt-on battery strap, which adds weight. I would suggest just using tape as it would be lighter and less likely to affect the way the chassis flexes.

Otherwise, you may look into picking up the Hiro Seiko aluminum & titanium screw set. If grip at your track is good, I would also suggest running the tires a little smaller.

Finally, what body are you running, and is it regular weight or lightweight?

Edit: I can't tell from the pic which axle you're running, but if that's the stock axle you will want to swap that out for the option graphite axle for a huge weight saving.