Is there anyone who knows if possible to put 225/45-R18 with 8x18" ET45 rim to new Ocu (std chassis), without any problems (touching mud-guards etc.)? 225/40-R18 should be okay, but I'd like to feel little bit more confortable tire : )

I presume you mean an Octy II. They have an 18" option I think on the new vRS so it should be ok unless the vRS has specific alterations to accomodate these. I doubt it though. Just watch out for an under reading speedo. Mmm. Maybe that doesn't happen anymore.