it's not a GTR badge for starters, It's a 2500R badge (I have no idea how he got it or where he had it made or anything)
and yes, it is just a beefed up RB25 but ... long story short, there is no such thing as a 2500R...
Legend goes that there were 3 cars taken off the production line to sort out a special type of car, like the 400R, but now imagine if the 400R never got put into production... You are left with 3 prototypes that lead to nothing...
That's what Malcolm bought... a pre production prototype. Albeit there is only one left and it's his, but there's no paperwork to backup such claims and how it looks now is definately NOT how it looked when he got his hands on it... it looks way better in my opinion, but some reckon he ruined the heritage (if it exists). He took a stab at how it would have looked and driven, and I think he did a good job!
That's my understanding on the subject