$300 each or $577 for the pair is a fair price for sure, not a big resale potential on an 18 inch bass cab in the light weight world of today.... so you may end up just eating the price.
I've always been drawn to the S12 and D12 cab tones, but there is something killer about those BE 18" cabs. They are huge and deep sounding, but not as boomy as some.
I recently tried to get Jim to make me a birch big box 18" powered cabinet to run as a sub with my 200 watt tube rig and pair of D12. In chatting on the phone, he sold me on the idea of a powered Infra D12 built to match my current pair of regular D12. The gig I was planning that beast for fell through, but I might have it build eventually anyway.