occupant

I don't know if the company is a vendor on here so I don't want to mention the name, but I wanted to know if there is any point is having a totally stock vehicle tuned? I'd like to take my 2000 model 5.3L Suburban down there, I'm willing to spend the $250 plus the trip cost to get this done, my wife is still on the fence about it, but I think it could make a good difference. I've never done a test/tune before. Complete idiot here. I'm going to ask the dumbest questions in the next few lines.

I have a fresh set of plugs I could put in it. Should I do that beforehand, or take them with me, or change them after?

I am 800 miles into my current oil change and about 6500 miles into the current fuel filter. What are reasons pro/con to get these done right after a tune or should I wait until the normal interval? I go 5000 for oil, 30000 for fuel filter.

I have a fresh (8000 miles) Goodwrench transmission in the truck. It shifts nice. Cooler and lines are new. Will having a tune done void the 3yr/100K warranty on the transmission?

The truck does surge a wee bit within the first minute or so of a cold or warm/hot start. No CEL or codes. Haven't looked into it. Will this condition affect the quality of the tune?