New 2007 g35x owner - tire/wheel options

[drrust]

I purchased a used 2007 g35x at the beginning of January. My previous vehicle was a E36 BMW M3. With that vehicle I had to use winter wheels to get around when the season came. Although some may find the all season tires on the g35x to be adequate, I find they lack grip even with a bit of snow.

My car came with the stock 17" rims running 55 series tires. My options would seem to be getting another set of 17" rims with snows from TireRack, getting some 18" rims with summer tires and putting winter tires on my current rims. As 18" rims will use a 50 series tire it shouldn't make the ride that much rougher. What is the consensus on running 18's and the impact on the ride?

Another factor is that on the winter wheels we have for my wife's Sienna, Tire rack had you use specific lug nuts for the rims. Although they sent a special lug socket, you have to keep as set of the stock lug nuts in the trunk to use with the spare if you get a flat. I've been thinking about getting some OEM rims (used) but still haven't found a style that I like. There is a set of 18" M35x wheels for sale local but the rims look heavy and they likely have 45 series tires on them. What rims will use the stock lug nuts on the Infiiniti/Nissan?

Thanks for your input.