Do anybody know this place?
 

It looks fishy to me and can they import automotive engines that is not certified here?

https://www.dieselrus.com/

I'd say if you're not sure about them, don't buy from them. Certainly the person designing their website has a limited knowledge of English for sure.

There are a number of dealers in SoCal who import used Japanese engines and sell them here as replacement engines. Usually they are automobile engines which may have approximately 40k miles, and apparently are no longer compliant with Japanese emission regulations due to what they consider excessive wear. This is a statutory regulation, and does not mean that there is any defect in the engine itself. I have purchased them in the past, but not from this particular dealer. Often the engines will come with a modest warranty, and I would advise someone to visit the dealer in person before making a purchase decision. As with any purchase of a used item, caveat emptor...