The Reedy ceramic is a little pricey but is a great quality bearing. I have noticed immediate and obvious power gains as soon as running the VR with a ceramic swap.
I can't gaurentee the proper fit of a Boca or TKO but here is a Boca link, looks like their ceramics are about $45 for the good one. In the past a couple guys tried to use the TKO but the fit wasn't correct on the OD. The deminsions are 14x25x6.
http://www.bocabearings.com/search.a...thOperator=%3d
Not sure if the bearing you get is the one pictured, but the Reedy bearing is made up of many more ceramic balls of a smaller size, and the Boca appears to be fewer and larger balls. The Reedy bearing is unique, and I'm sure this was engineered this way for a reason.