D2 is a budget coilover sold pretty much world wide even in japan.
Even used on Japan Gymkhana champs wrx with d2 8pot front and 6pot rear.
If you want to go ahead with D2 contact Justjap in Kirrawee.
www.justjap.com
THey give a proper local warranty and you get a proper receipt. If the dampers do blow after warranty you can buy off the shelf damper inserts.
MDU on the other hand are not heard off other than on ebay. Its purely an ebay originated house brand from an unknown manufacturer.
So you can make your own mind now on what is the better option in the long run.
Dont buy these coilovers from these ebay traders especially frmo overseas.
If they do have any problems you will have to send it back overseas.
For what. Just to save 180$?