I have 3 years validity in my passport, if I apply for the dtv visa now( 5 years validity), would there be any problems when I renew my passport later.

US citizen here already in Thailand on a 60-day tourist visa obtained at Suvarnabhumi Airport getting ready to exit at the end of next month heading for Cambodia and three weeks in Siem Reap.

Taking the Giant Ibis VIP bus service over and understand that the company will help passengers in getting their land entry documentation and I pay the visa entry fees there on arrival.

Will be taking the Giant Ibis back to Bangkok and wanted to know should I experience anything different at a land border crossing coming in from Cambodia since I already have had a Thai visa stamp (albeit expired) and they have my picture and fingerprints. Do they just stamp my passport with another 60 day visa? I'll be heading for 3 months in Vietnam before that 60 days would expire.

Thanks for any help !