xray shocks do not need to be rebuilt that often at all. you can probably go half the season or more on a fresh build assuming you dont change the oil in them and build them properly.
during a race day, assuming you havent had a massive accident, its just a matter of blowing the crap off the car, making sure all the axles and belts move freely and there isnt any binding. make sure all your screws are still there and are tight. if you have a bad accident that involved a broken suspension arm or top deck or similar, it might be nessisary to strip the car when you get home to check for alignment and stuff as suspension holders and bulkheads can get out of alignment.
after a race day, i might check some of the bearings to make sure they move well but ill usually just back the motor off its mesh and I can tell right away by how the belts move. checking cvd pins should be normal as they tiny setscrews in there often come loose and start to mess up the steering block/uprights unless they are bearing captured.
really, id just start watching the habbits of people who win races at your track, and copy them for the most part.
otherwise, most of the stuff on these cars is pretty common sense. if its broken, replace, bindy, replace ect.
Jilles Groskamp posted a great series of youtube videos on how to properly build a touring car, at least his touring car. Schumacher has also posted some that I found useful for building and maintaining shocks.
Sanwa M12 - Xray T4/16 - Xray Nt1/16 - CRC XTI-WC - ProAMPS - Hobbywing - ReVTECH - ORCA
www.irocc.ca - www.wcics.ca - www.vrcworld.com