have you had a read of the knowledge which includes an updated section on the range of hybrid turbo's available
what sort of power are you looking for
0.86 is the a/r ratio of the turbine housing, the larger it is the more it will allow the turbo to breath at higher rpm's and produce more power, the downside of this being that low and mid range response will suffer meaning that the turbo could feel quite laggy
0.49 a/r is the standard turbine housing and is the size used on all hybrids, next most common size is the 0.64 a/r housing used on the garrett ball bearing range, 0.86 a/r housing and larger are also available on the range although unless you are going for big power i wouldn't use one
