Looks like a typical Kustom rig, what's slanted about it? If the baffle is angled up towards your ears slightly, that's fine, you'll only hear yourself better. If you want a brighter sound, more highs, some thing that coukd double as a guitar cab, consider EV 15L's. Warmer bass sound with a boomy bottom, Beta's do that. Warmer bass sound with a smooth bottom, Legends are the ticket. All three of them will work in a sealed design should you deside to plug the ports. Delta 15's will handle up to about 100 watts worth of bass too, and are probably the closest to the old CTS, Ampeg B15 speaker sound. That's what JimmyM says, who's ears I trust. He has B15 cabs with both original CTS's and Delta's.