Willy I believe it is permanent, they did advise me that my ECU is a tricore so does have to be opened up to be programmed. Now as well as that these are the gains;
Power (bhp):123 bhp to 140 bhp +17bhp
Torque (lb/ft):148 lb/ft to 170 lb/ft +22lb/ft
Which lets be honest is a banging deal for £149.99 especially when you're looking at £300+ most places. Not only that the more people you use the larger discount, they are 3 of us looking to get our cars remapped and was advised it'd be around the £130 mark. I have also emailed super chips a few days ago advising my car can be experimented upon.
Sounds like a good deal at that price and very tempted.