I think the LX2 is an outdated model, parts are getting tough to find, so its really not worthwhile converting to one.
It would be easier to upgrade what you already have.
The proper tire can make substantial performance gains. Its good to have an assortment of tires on hand for different track conditions.
New shocks, servos, rechargeable battery packs and 2.4ghz radios are great upgrades compatible with just about any model of buggy.
And if you really want to kick it up your buggy's potential, get yourself a good engine/pipe/clutch combo
Last but not least, hone your driving skills, you should have no problem competing with anyone.