Aircooled!!!!
You are Poland! Bis parts will be hard to find, they were really not popular.
There are thousands of great 126s in Poland. Look on Allegro, go to any of the 126 Polish sites. You will pick up a decent 126 for 600-1000Zloty.
Honestly, don't get a BIS in Poland. I lived there 13 years, looking for Bis parts for people.
I assume you are English, remember if you drive a 126 in poland people will treat you like poo. they will not understand why an English man is so poor and needs to drive a rubbish car. (Polish thoughts not mine)
Good luck in Poland. You will need it
