I've got (or soon will have) an RRA M4 profile at 14.5" with a perm Phantom and was thinking towards the future.  Right now I've still got the standard M4 oval handguards and fixed FSB.  

When the barrel comes back and we pin the FH, I was wondering if it would be more advantageous to use a gas block I could take on and off (if need be) without needing to pull the FH off.  Something like the YHM 2 piece here: secure.valinet.com/~yankeeh/cgi-bin/web_store/web_store.cgi?page=sights.html&&cart_id=7650611_19930  Then get a flip FS.

I've been thinking of the YHM 2 piece handguard so this would work well together, but if I don't go for that it's no big deal either way.  I don't have much else to do to this one besides the above and hang a light on it.  The overall build is for a 'CQB' type rifle.  I don't really have any interest (or money) in a free float tube for this build.

I'm also not sure if I'll need any of this and should I just go with the original fixed FSB and if I need/want to I can just hack it off later and go with the 2 piece.  Maybe I should just save for the next build.

Suggestions and comments welcome and requested.  I guess I'm trying to finalize what this rifle will end up as and I'm looking for ideas.

Thanks!