P3steel 4 - Y-axis belt tensioner

I got a P3Steel XL frame, which is the v4 with 20x30 bed.
The kit did not include very good parts and still has some design flaws like toolson mentions.
I made this remix to improve quality of the printer.
Since the quality was not that high on initial prints and the outer walls of the nut traps and screw holes were full of gaps I decided to add a little material around them.
The v4 frame as plenty of room, so it does not interfere with the axis movement.
I also added some little supports t