Parts? It seems that Towerhobbies is the "exclusive" distributor in the USA. They carry a fairly full line of parts and claim that they should have no trouble getting them. Their prices a questionable though.
This model is going to take a while to pick up steam....remember the MRX is about four years old or more.
I am currently in Tokyo on business and I picked up an Evolva last night for 470,000 Yen plus the 5% credit card thing....about $420 with todays exchange rate.
I bought from http://www.rc-champ.co.jp/
Use Alta-vista.com to translate the sight to english (translate in small orange type under the search field)
They have a full line of parts too. I'm coming home with a full suitcase!