there is quite a bit - has been covered in a thread a while back but off top of head...
larger wheel bearings, larger and different / lightweight hubs (alloy), larger ARB's, possibly different internals (not sure) larger brake discs, different calipers, possibly different injectors (again not sure). More power.
The mods on the silver one are pretty good from what you can see - there could do with being more detail on the actual engine components used but Bob Rawle has a very good reputation for his work, all of the external stuff can be reversed to standard no problem.
Thrashing a scoob is no issue if you warm the car up properly and cool down after, it is the poorly maintained examples you need to look at with a view to corrective maintenance.
If you are willing to take the time you can get the right car for you - a lot of the newer cars tend to be owned by the 'ahem, cough' more mature owner that takes a bit more pride in ownership as insurance can put many potential younger owners off + the £500 tax isn't as attractive to those with a tighter budget.
But the ultimate standard low mileage non thrashed examples are brand new in showrooms - that is the only way you can be absolutely certain - otherwise it is service history and former owner.