The Pro 325, 350 and the 380s use the same case which is about 3 inches wider
than the Rainbows. The Pro series can be upgraded by just swapping the
Motherboards. They also have an interior upright cardcage for the accessory
cards. I think this is why they need the larger case.
In the Rainbow the accessory cards lay parallel and on top of the Motherboard.
Both use different floor stands that look alike but are different sizes.
Paxton