Bingo Airsoftworks just made putting an HPA Engine on your ICS L85/L86 AEG easier with this replacement kit they released... "The Bingo Airsoftworks ICS L85/L86 HPA Engine Gearbox Replacement Kit is now available. The HPA kit allows you to easily upgrade your ICS L85 to use the Wolverine SMP (it will also work with the PolarStar F1 and Wolverine Hydra, when available). The kit includes everything needed to convert your L85.