depends how good of an example it is too start with i would say, if its been looked after mileage isnt an issue, my old bugeye was on 144k when i got rid and that made 272 bhp on the rollers. 
  
if i was you i would say, 
panel filter or cone 
exhaust system, with decats 
remap 
fuel pump 
this will see you about 270bhp mark depending on turbo, and these arnt really mods to make potential buyers avoid either.