These were bought for a Harley Benton PB-50 mod project. Iwas going for the original 50's look so string through body was a must.
Since the PB-50 was ordered from Thomann it made sense to order the bushings too. The price was also better than I could find in the UK.
Very easy to fit. Once I'd position my 2 saddle bridge I bored pilot holes then flipped the bass over. A 9.5mm countersink finished the drilling. A tap with a rubber mallet saw the bushings secure.
If you want the bushings lying flush with the back of the body use a 12.5mm flat bit to the depth required (2mm I found) before using the countersink.
No "cons" were discovered. It's a very simple product that works well. Highly recommended.
You can see the finished PB-50 on bassic.de, basschat.co.uk, onlybass.com and talkbass.com. look for posts by kodiakblair.