They are great. They do include the longer hop-up titanium shock shafts though. This means they need a bit of limiting in the rear to keep the dog-bones or CVD's from falling out of the outdrive on the DB01. The fronts seem perfectly fine on mine without limiters.
Tamiya's writeup recommends two o-rings as limiters to get the job done in the rear:
http://www.tamiyausa.com/articles/fe...article-id=414
The DB01-R kit has the shorter shock shafts from the original 501X kit. The kit instructions recommends a small 1mm plastic spacer as a limiter.