Bearings are graded on ABEC scale, and Boca's only ones who list their rating. I'm assuming most are grade 1/lowest, or they'd be bragging about at least ABEC3 status.

Boca currently has metric bearings for this car on sale in individual pieces, ABEC7 level for $160 to get 415 setup. This does not include 2 bearings for diff, or 2 for steering. Kinda spendy, but you can't get bearing that are higher level.