(adsbygoogle = window.adsbygoogle || []).push({}); I have a PS3 on OFW 3.66 and a PS3 on CFW 3.55 and i'm wanting to know how to host CL on Mw2

Put the Modified patch of your choice onto the CFW Ps3 then once it's on simply data transfer your CFW ps3 to your OFW ps3 and the patch will transfer over.
If you dont want to lose any data on the OFW ps3 i suggest you back it up before doing this because data transferring re-formats your HDD

I've read about that I need a 3.66 spoofer, or is that not needed?

That's for transferring from 3.66 to 3.55 .

No spoofer needed you only need the spoofer if your data transferring from 3.66 to 3.55 CFW.