How to know what rim is compatible for 2006 Impala LS
 

I have an 2006 Impala LS that came with the standard steel rim with hub caps
I am wanting to get stock SS rims but not sure what size is compatible for it.
let alone, which is best overall. im not a fan of the big 22" ones
I know I have 225/60R16 tires on it and the bolts pattern is 5x115 I believe with a Rim width of 6.5 I read that many mention offset & bore size with describing the rims. How are these values determined for getting the correct wheel?

Any help will be appreciated. Thx

06 Impala LT
 

I have 2006 Impala LT stock 17 inch wheels and 235/55-17 snows on now.
I mount my SS stock wheels in the summer with 245/45-18 rubber, I'd like to go bigger with 245/50-18.
Tire Rack says a 245/45-18 will safely fit. The bolt pattern is the same for LS,LT,and SS