Here's a good read from Flat 6 regarding the upgrade installation. Seems like they will give the Box a thorough inspection both pre and post installation of the new bearing as part of their process:
The Flat 6 IMS Bearing Retrofit in Detail - Page 4
As a new owner, I would really want to feel comfortable with my shop before I went ahead with a procedure like this for preventative maintenance. Seems that if the bearing removal or install were botched, (or anything else along the way), then I'd also have things to worry about - and may not even know it.