I have just left Iran, 5 days ago. Whýlst I go the výsa ages ago I had no problems extendýng ýt a lot! I broke down ýn Kerman and ýt took a month gettýng the býke out and back to repaýr. In Iran there are no problems, there may be a problem gettýng one from outsýde - get what you can, but NOT a transýt výsa, and extend when you are there.
There may be problems now though as when I left there were a load of antý-western demos, partýcularly ýn Tehran, and the posturýng ýn Iran ýs as bad the other way as ýt seems to be ýn London.
If you do get one ýt ýs an amazýng place! But two býts of advýce. Take double the money you thýnk you may need as ýt gýves you a good fall back. And dependýng on the býke take plenty of spares. I have a KTM whých self destructed but spares were lýterally ýmpossýble to get. I had loads of servýce ýtems and býts and pýeces but the part I needed I dýdnt have and ýt gets dýffýcult then!