fastharry,
I have the TiR titanium pillow balls on my car now, but as they need replacing I'll put the stock steel pillow balls back in. I have been very happy with the TiR pillow balls, just getting out of hand with the titanium, too much cash and not always enough supply to meet the demand. I may try the Mugen pillow balls and see how they work (I have alot of friends that run Mugens, I'll hit them up for some freebies).
dvargas,
I don't know about the XTM, but the Dynamite failsafe is brand specific, you'll need the Airtronics version for your MX-3 (a very nice radio for the cash by the way). I don't know if it will work on the stock RTR radio. The XTM is advertised thru several vendors in each issue of RC Car Action, check it out there. You may also find it somewhere like Tower Hobbies on-line. They should be able to give you the technical info you need.