Looks cool, that's for sure.
Me personally... I would plug those ends to prevent any corrosion from entering tube.
Also I would make a mount for JS, that way you are not committed to it, if you want to change drive line options in the future like a TAV unit.
I made a TC mount out of 1/4" thick rectangle 12" x 5" x 3" tube. I used a bearing tube and angled steel to weld to the rectangle tube.
You could just use some 1/4" - 1" thick plate instead.
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