Hi Joe. We can’t give you a definitive answer as to whether it’s worth it, but we can tell you what you need to consider when making your decision.
The peak power (64 vs 78 bhp) is probably less important than the power throughout the rev range. So, how much improvement is there at low revs and mid-rage revs, rather than just the peak improvement at high revs (which you will rarely ever use)?
If your car is still under warranty, any mapping modification will almost certainly void the warranty. This will make any failure – even if it is theoretically unrelated – potentially much more expensive.
There may also be insurance implications for altering the mapping – you need to declare the modification to your insurance company and they may well hike your premium as a result.