I just got a slightly used unloaded 4x12 (straight) Splawn cabinet, delivered on Friday. The first set of speakers I tried in it was an X of V30 and G12-H30 Hellatones, originally from my Avatar Contemporary.
History: In the Avatar, they had this harsh grindy 'spike' that didn't go away with break-in. I even tried each speaker in a 1x12 I have, they all sounded great alone. If I hooked them up to just use one pair or the other in the 4x12, they sounded good. I replaced them with a mix of Warehouse Vet30 and ET-65's. It (Avatar) sounded really good, but there was a little bit of mid 'honk' that I couldn't dial out when doing anything with higher gain.
Current day: So I put the Hellatone mix in the Splawn, almost exactly the same spikiness. Pulled them out, put the Warehouses in, still had some of that mid-honk. Not as much as the Avatar, but it was still there. I wired it up so that in stereo mode, I had the Vet30's on one side, ET-65's on the other. Vet 30's by themselves sounded a lot like a nice set of of broken-in Vint30's. However, the ET-65's got me much closer to the 'modded 80's' sound I was going for, so I ordered a second pair of ET-65's for the Splawn. Once they come and are broken in a bit, I'll post what I think with a whole quad of ET-65's in the Splawn. My Splawn came with recessed square-headed screws, BTW.
On a lark, I tried wiring the Hellatones back in to the Avatar, but instead of series/parallel or parallel/series, I wired them all in parallel, 4 Ohm load. They sounded so much better that way... It also made me glad to know that the Avatar can hold its own with the Splawn, at least in terms of the cabinet itself. Speaker choice seems to make the biggest difference.
Pic of the cab: