Nearly 100% right, Fred. The A3000, like its 'big-box' brother A4000, takes the CyberstormPPC, with the BlizzardPPC being solely suitable for the A1200. Both were designed and made by the same firm.
The BlizzardPPC connects to the trapdoor expansion slot like any other A1200 accelerator. The BlizzardVision graphics card connects to the BPPC.
The two models are roughly equivalent in performance, with the CPPC shading it. Just ask if you want to be bored with some info about stuff like bus speeds, FPUs, context switching and memory addressing.