Well Thom, they are the same thing and a super chip / Re map wont harm your car but to get the best of a re map you may want to uprate your engine with after market parts. A good place to start is your air filter. Replace your standard one with a cone filter, i.e a K&N filter / induction kit will bring more cold air into the engine and increase BHP then do the re map to increase it further. Or go for a bigger turbo, there will be slighty more turbo lag but once it spools up it will dramaticly improve acceleration and increase your BHP a lot. There are many things you can try like 'Blow off valves' too to increase accelleration, depends how much you want to spend.
Well it depends how much money you have to spend. My favorites in order are: 1. XJ220 2. XKR / XK8, 3. XJS V12 (80's-90's), 4. E-Type, 5. S-Type R / S-Type, 6. XJ, 7. XF, 8. XJ (New) 9. X Type R / X Type.