Fane Colossus 18XB 1000W AES

Hi all, I need to up the anti on my rig, and so I'm looking to build a couple of sub bass units. Powered by something like Cerwin Vegas CV2800 amp or similar.
Any suggestions based on the above speaker chassis gratefully received.

Lets start with; What's your budget? I would suggest building two G-subs and load them with Fane's. It would give you lots of low end bass, high spl and is easy to build. Using 8ohm versions, you would put the speakers in parallel and use one amp (CV2800-bridged) per cabinet.
More info would make it easier for me to help you; Audience?, What's your current setup?

Budgets ok - ish, don't wanna go too mad, but I could buy the 4 ohm version Fane. That said, G-Subs may well prove to be the kiddies, my audience being in large marquees, etc. sometimes outside. My current setup won't cut the mustard, subs and tops Cerwin Vega Intense (passive) and one CV2800 Amp, but cheers for the advice patryk1305

Fane XB's are apparently really good in G-subs. G-subs loaded with Fane XB drivers should give you an output of over 130dB without a problem!

Look at these two videos of G-subs (XB loaded), these are not mine.