Most of the KKK K26 turbos were off of Audis and Porches with engines around 2.1L. I think it is based on an old design, so it probably isnt as efficient or fast-spooling as today's turbos. It probably has a unique exhaust housing flange too, making it harder to buy/make a manifold for it. Are you going to get one cheap or something? If so, does it have a watercooled center section or just oil? If its cheap, I'd still get it.
And I believe KKK makes large turbos also, but dont hold me to it..