Suggestions for maintenance at 106k and wheels/tires questions!

I've recently got a 00' Silverado Z71 and just over 104k. It's a clean truck and everything checked out when bought from the origional owner who got it with all the options, leather, heated seats, ect. It even has all of the "reminder mileage" stickers on the door for upcomign oil changes and it's in amazing shape for the year and mileage. Only wear and tear is of the drivers leather seat, but all other seats are perfect... no other signs of wear, even the underbody is perfect and has no marks of scratches to indicate any type of off roading.

So, here I am about to take it for an oil change as indicated by the last "reminder sticker" and was looking over the owners manual to see what else I should have done. Given the quality of the vehicle it likely the previous owner had everything required done on the last maintanence. But, I'd feel better about knowing it's been done or atleast having it checked along with everything else to be sure it has been. So any suggestions would be appreciated.

Now for the other question, the one thing that is needed is a set of tires. Currently it has 285's on the stock wheels. I've heard 285's are the typical max on the stock suspension so I'll likely stick with them. But, I just came across a set of 16'' Pacer wheels mounted on Wild Country Radial CVT 285/75's for $800. The tires are nearly new, less than 1k on them. The wheels are off of a 97' Silverado, which I'm was under the impression have the same lug pattern. Would I have any issues with this tire wheel package on the stock suspension? I'm have a leveling kit installed later this week, which may help if there is an issue. Any feedback is appreciated, and is $800 about right for this wheel/tire package, there in great shape?

replace plugs,check plug wire resistance,use dielectric grease on plug wire boots... transmission filter, and fliud, if dark and cloudy replace fluid 3x,replace transfercase fluid uses trac II,front and rear differentials oil and on rear remove cover to inspect and clean off magnet...when replacing tires rotating check brake pads and calipers for binding.....inspect brake lines in the drivers side front frame rail for corrosion, replace power steering fluid i use prestone and pump is quiet, fuel filter, you will probably not do this but to keep the engine and cat exhaust system from damage replace the upsteam o2 sensors with the exact same ones....100,000mi is the replacement interval....

as a warning do not get transmission flush this will cause problems.......get the fluid replaced as the repair manual states no flushing...as particles will get into the valves and you will not be a happy owner.......
good luck

Has the transmisssion fluid and filter have been changed?That is one to have done and GM does not recomend flushing a transmission,says in the service manual.Change the fluid in the transfer case, use only Auto Trac II only and it sold at the dealer.GM started using Auto Trac fluid in 1999 instead of ATF in their transfer casesand takes about 3 1/2 quarts of this fluid.

What lube do you use for a posi(G80) rear end?

What lube do you use for a posi(G80) rear end?

this is the locking diff that i have i use mobil one synthetic gear oil 75-90wt..... remove rear cover and clean debris.... use drain plug so that you don't spill... if you don't take cover of don't bother to change oil...fill to 5/8 in below fill hole