Also, if you listen to the clip, Little Mr Hammond says they are going to "Cheat" and fit NOS
The Jag is also a V12 - Proper performace mods could be a set of TB's, pair of turbos or a supercharger - or all 3
You could also add some race fuel - summut like "Cool Blue" Works in a very similar way to NOS in the way it has O2 in it - advance the timing 10 deg or so, increase the fueling, and if you did the turbo conversion, you should see a 30-40% gain in power