It is a problem known as "bump steer" that the Losi suffers from a bit. The car will be fine without fixing it, but others have found you can increase performance in a few ways. Do a search of the "Losi XXX-S" thread here in this forum for some further information on it (it has been discussed a lot).
The most common thing is to add a small washer to the inside of the carrier to prevent CVD's angle from overextending. There may even be information on this on Losi's site. Actually, take a look at the XXX-S Tech FAQ, which can be found in the Articles section off of the R/C Tech homepage.
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