Yes, they can. They must be mounted as a pair.
Yes they can
Yes. I've done it. Fits well.
Doubtful, that is a big change. You can usually go one size up or down with no problem, Not three.Doubtful, that is a big change. You can usually go one size up or down with no problem, Not three.
Yes, you can use a 225-45-18 tires instead of 225-50-18 tires.
They are Taiwan designed and now made in China or Taiwan. I got NS-2 and my fronts (225 45 R18) have "made in Taiwan" mark and my rears (245 45 R18)have "made in china, designed in taiwan".
There are a number of options when you want to buy 225 45 18 tires. One can check his local tire shop for these specific tires, or a local car shop. Alternatively, there are a number of tire manufacturers, such as Pirelli and GoodYear, that sell these tires on their webshop.
It is possible to find used 225 45 17 size tires on Ebay or Craigs List. Also check local recycle or junk yards to see if they might have used tires available.
Yes, I Have 18" Rims On My '99 LHS.I Have 245-45-R18 Tires, With No Rubbing At All.
NO, that is a very radical change and may rub steering tires on the frame.
The GCF is 45.
45 out of 225 is 20%
180