Best oil/oil filter for 2001 5.3L 180,xxx miles + maintenance recommendations

[rchadhaney]

I just recently rolled over to 180,000 miles on my Tahoe, I bought the vehicle last year with 166,xxx miles on it and since then I have replaced:

Water pump (started leaking about 4500 miles ago)
Fuel pump (shortly after purchase, tahoe was hard starting and under powered)
spark plugs
plug wires
fuel filter
air filter

I've been running Valvoline Synthetic with Fram high mileage oil filters. Recently I started researching oil filters and just realized how bad some of the FRAM filters can be.

I am pretty happy with valvoline but somewhere I read Pennzoil synthetic is actually better? I don't want to spend the money for Amsoil but what do you guys recommend for synthetic oil? Or should I just stay with Valvoline?

What oil filter should I use for my next oil change? I want a high quality oil filter, I only change my oil very 6,000 - 7,500 miles.

What other maintenance things should I do on the engine? I have done the 3M complete fuel system cleaner once ( Amazon.com: 3M 08963 Fuel System Tune-Up Kit:...) and then since then I've been running chevron fuel cleaner at every oil change.

I also am thinking I need to do a complete coolant flush (I didn't flush the entire system when I changed the water pump)
and I'm thinking about a new filter and tranny fluid for the tranny.

What else should I do? at a 180,000 miles this tahoe still runs great and I am hoping to get another 60 - 80k on it..