05 Boxster (987): Upgrade 17" Wheels?

[luci5r]

Guys,

I have an 05 Boxster (987) that I'm looking to do some work on. I have owned the car for about an year, and even though I'm trying to learn as I go, my technical knowledge is limited.

One of the first thing I'm planning to do is replacing the Rims/Tires on the car.

This is what I currently have:

Fronts: Continental SportContact2 205/55 ZR 17 91Y Radial Tubeless
Rears: Michelin 235/50 ZR17 96 M+S Tubeless

My understanding is I have 17" Wheels. I have two main questions:

1) Is it possible to upgrade to 18" or 19" wheels? Or do you have to stick with the size that you currently have? I have an Indy mechanic/workshop that will be doing all the work for me. I'll probably purchase the rims & wheels myself.

2) Can someone recommend me good tires for the car? I'm not looking for racing tires, on the contrary, tires with good traction for basic city driving. I will be replacing all 4.

Any advice / suggestions will be appreciated.

Thanks!