High milage AV

Hi all. I just recently bought an AV with 233k on the clock!  So I have a few questions. Previous owner said he used high milage synthetic blend, what do you recommend I use? And now that it's warming up I want to do a full tune up. What all should I look for/change other than just plugs and oil? Thanks!

Since you don't know the condition of all the fluid I would add Tranny Transfer case and both front and rear differentials Also coolant

I'd change the transmission fluid and filter, but not do a flush.

I'd also change the front O2 sensors.

Make sure any recalls have been taken care of.

I've checked recalls and none to be found. I just change out the rear pads and rotors yesterday. And am planning to upgrade the fronts to the newer style since it's a direct bolt on. But now my question comes to motor oil. What oil do you guys recommend? I've seen where Rotella T and T6 have been used in ls motors. But idk how good it would be given its heavy duty oil and this being so high in mileage. So what do you guys think?

And what plugs and wires should I go with? Thanks!

I'd probably stick with a high mileage synthetic blend.  5w30 if in an area with big seasonal temperature swings like the Midwest.

Plugs - I'd put in NGK TR5IX.  Wires - pick something that looks good from a good aftermarket brand for LS1 engines.  Do a search on Summitracing web site.  I've used Taylor and Crane myself but there are other good choices.