I just got mine in Jan.... It's got the 7 year 70,000 mile warranty so if it dies oh well... guess it's on them.

As for putting bigger tires on, yes you've got to watch what you do to new trucks. A lot of stuff can void the warranty. for example oversized tires. If you want to do stuff like that to a truck your best bet is to get an older on. I had an 86 Ramcharger that rocked..... I just got tired of working on it.