I'm not sure what bearing it is, looks same as the ford one, but it's just bigger in the middle Also there is a huge difference between single piece and twin piece shafts... Twin can handle a lot higher Rpm, because less vibration
Pretty sure my FG shaft got re-tubed with 2.5" .095 I also had the stub for the centre bearing replaced as it went up in size to allow for a bigger diameter bearing and a larger uni And got the CV rebuilt Here is a pic, can sort of see the difference Mine is not for a 1000hp or anything but it is a hell of a lot stronger than standard And don't hold me to this but I think the standard was 2.25" .040 And he is a pic of a tailshaft size to rpm limit chart that I have seen before
Your mum drives your 400kw+ car around ? And I'm confused a little bit, your box has blown, an now your rear end has been smashed ? I'd take the box back to the original if he offered warranty