You wont need to have the external 'thousand-pound-a-time' tests, just the simpler tests... the topic has been covered many times, but its such a common thing, that I think there should be a couple of pages somewhere with all the details of whats needed...
For my R32, i needed to buy...
rear Fog light + illuminated switch
Side indicator repeaters
Speedo converter
Fuel neck filler reducer
'E' marked 'H' rated or higher tyres
My car took 2 attempts to pass... it failed on noise, tyres, and a loose amplifier wire the first time...
hope that helps...
Matt