I decided against it. My decision was 1) too much extra PoundsPoundsPounds that would be better saved, 2) looks like a Carlos Fandango add on* that a Max Power teenager would save up to buy from Halfords and offseting that was 3) the advantage of a more aggressive PSM map... but for the 98% of the time I'd spend on the road I'd not get the benefit of it.

*Alright... maybe a bit harsh.