I have a 20i N20 X1 which i picked up my car in July 2012 and running 5,000km today in Asia Hong Kong.
Ordered my tunes from Terry when running 3,000km and installed at 4,000km. Tunes is worth it as it really minimised turbo lag (20i has great turbo lag @ 184hp on N20). Running it for over 1,000km and have no regret other than manual reset of throttle and/or disengaging power in car for tranny behaviour.
If disregarding the tranny behaviour and throttle lag after computer learning your style of driving behaviour in a city mode, the BMS tunes are worth investing as it does not affect fuel consumption and it really helps minimising turbo lag.
I've made a compliments to Terry personally wishing him to develop the Stage 2 tuning for N20.