a car from 2005 would be fine. The problem is the CKv3.1 didn't come out in '05, it came out in 1998. Even still, the car will still work very well. The problem is that it was discontinued long before brushless and lipo came out. the lipo part will be fine, but you wont be able to upgrade to a brushless offset rear pod.
If you are going to buy a used CRC car, buy a gen-x car. doesn't necessarily have to be an xl because at least you will have the option to upgrade later if you want, where you won't have the option with the older CK.
John