As a guide price I have the 2013 Airlift Perfomance struts the same as N8 has with the better double bellow rear bags, Airlift V2 (Which is better in many ways than Accuair), single 380c Compressor and stubby tank fitted £2450.
Accuair is very good but its alot more expensive and theres alot more to go wrong. In my opinion I'd take airlift everytime.