Just to add the Car Builder Solutions universal gaiters I linked to above are easily chopped down to the size to fit. I offered these to my dealer on the understanding he would fit either MMC warranty one's or mine dependant on which was the more supple and therefore less likely to split again. He chose mine, the CBS ones.
The gaiters can leak from the ends where their lips fit into narrow grooves in the racks main body. They are secured with plastic cable ties which can be replaced by more durable steel ones. Cain at Wolf Performance suggests these ties are wider than the main body grooves though, so do not exert pressure to give the best seal. He advocates narrower ties to better match groove width, also allowing better location.
I would suggest that even if gaiter(s) appear intact when attempting to cure a leak, they be replaced then as its only a matter of time before the less compliant OE ones will split, on recent cars at least. This would have saved two independant warranty claims on my car never mind the inconvenience.
