Cost - £200-£400
Is it reversible - Yes
What does it actually involve in simple terms - A man plugs in a laptop and tweaks stuff!
How much will it affect my insurance - Depends on how old you are, i got a quote for modified car insurance for the first time this year and it was cheaper than the unmodified quote from my previous company.
What are the different types, and which is best (REVO? plus 'ive read about others) - Custom Code, Revo, AMD to name a few, they are all very much the same, I have used AMD in Essex for my last two cars and been very happy.
Where can i get it done? Ask Google to find your nearest place.
My car has just over 70,000 miles on the clock, will the car be able to deal with the extra BHP? Maybe, the clutch can slip, may need to upgrade, or just live with a bit of slippage. I am still running a standard clutch with no issue but will upgrade when it gives up.
Will i need to modify my car, ie better tyres? breaks? It's always a good idea to upgrade your brakes, always have good tyres(no budgets) and better suspension won't hurt. I have not done my breaks
Where can i get the remap done? You already asked that.
Realistically how much more power should i expect to see? I got another 40bhp (2.0TDi 140bhp now at 193bhp according to a RR, not sure its that much though)