Welcome

Please do not use Google Translate. It would be better if You use English. I think most of users will understand You without any problems

I think importing parts from USA can be problematic because there are quite a lot of differences betwee US and EU models, (paintjobs, immo, some engine parts, ECU units etc). Maybe universal parts for US/EU models would have demand. You can try, good luck!

If You mean accesories it can be good idea. Lot of people would order some accesories from USA or other countries but there are 2 disadvantages: shipping time and shipping costs. First thing which I have on my mind when thinking "parts from USA" are exhaust systems. I think it can be good deal.

it is not to hard i think. If it would be so hard we wuold not have any US motorcycles in Poland (RJ12, RJ16 RN23 etc) but we have those. Even US versions are more attractive for potencial buyer because of paintjobs, You guys have extremally cool paintjobs of Yamaha motorcycle. EU versions just suck. For example RJ16 in flames or RN23 black/red, white/red white/blue etc.
I know few users from this forum who imported few motorcycles from USA, I can ask them If You want.

Going back to exhaust systems:
For RN22/23- TOCE (for sure )
RJ 11/12/15/16- TaylorMade, GYTR, 2B, FMF
For other motorcycles i dont know the demand.
On polish market we have overdosed Yoshimura and Akrapovic exhausts so it wouldn't be a good idea to sell it. Maybe when somebody has special order so then ok. Lastly people are often looking for 2B exhausts. But nobody knows the FMF company, GYTR etc. It could be good idea to introduce it on polish market.

yes they have but in Poland bikers likes when their machine is blowing flames from exhaust! only small group is using block off plates.
I dont know does it harm condition of engine but flames blowed from exhaust makes riders proud of their bikes