I don't think this forum is the best place for advice like this.. I got my rims and tyres 3 months ago and had no idea but any of this stuff..
There's simply too much information which is often contradictory.. The forum is only the place to get the basics like what 235/40/ZR18 and stuff means..
Go and talk to a number of different wheel and tyre places.. Some of them will try to rip you off, but get quotes from a number of places..
You can save upto $400 for a set of tyres by just going to different places.. No joke..
The only advice I have is to ask questions at first but as you go to more places, start using the knowledge gained from your inital questions to demonstrate to people that you know your **** and you're not gonna get ripped off..