What type of oil

Just rock the GTX if that's what you've run forever. No problem with that. Heck, that motor probably ran on conventional oil for the 100k miles before you, it's not going to be a problem now. One thing I noticed with mine though, with 10w-30 the hot idle oil pressure was a little low so I moved to a 10w-40 and the low oil pressure problem was solved.

Just for the record though, I run Rotella T6 in it now.