wheel size confusion?
 

Hi guys, just want to ask a question that's been probably asked many times before and I hope someone will be patient and answer this again.
I have a 98 4Runner limited 4x4, I am planning to buy new wheel and tires.
My stock rims are 16" as you experts know, I want to go to 17"
Can someone please tell be my current specs-"back-spacing" , rim width etc
and up to how large a tire I can go to without effecting anything. I'm trying to find Sequoia wheels online here and in Ebay but I'm worried about the backspacing issues.
Any advice great appreciated!!!!