yes royal purple is synthetic, and the antifreeze does need to be mixed 50/50 just make sure you buy a good brand. check to make sure your radiator isnt cinked or blocked off by anything like if you hit a deer, big bird, etc. and fram is a very trusted filter, some may have their opinions but its reliable. but i still say you should try k&n as you mentioned

 

It is in general motors engine specs for their gas engines to chew thru about a quart of oil or more. That's what a guy from general motors told me. I use calcimine max life 10w 30 in my 02 silverado and its doesn't chew thru as much oil as it did in between 3000 mile changes

 

For anybody who believes in fram oil filters:
Tech Review: The Long Waited FRAM OIL FILTER REVIEW! - Automotive Social | DSLReports Forums

(1 of many similar reviews)

K&N does not filter that great and I wouldn't use it IIWY.

I find Mobile one to be the best all around oil filter. Hell, even the wal mart
brand oil filter aint bad!