Lightweight bbl upper. Advice for hobby shooter.

I own a RRA LAR-15 with a 16" 1:9 heavy middy barrel. I have added a MI two piece drop-in rail with a Surefire G2 in a Larue offset mount and a Comp ML3 in a Larue cantilever mount. I would like to go to a lightweight profile barrel. My question is: should I buy a BCM lightweight middy upper and transfer my current upper's guts or get a middy lightweight barrel/FSB/handgaurd cap and install it onto my current upper? Take note that I am just a hobby shooter. For my purposes I am happy with the current setup that I have, but I would like it lighter. This rifle is also a stop-gap of sorts, if I like the lightweight profile barrel I plan on getting a BCM lower and BCM lightweight upper with the VTAC TRX 13" for classes/hd and use the RRA as a backup or build it into a hunter configuration.

Thank you
Patrick Scott

If you have the budget to buy a new upper outright, you'd be hard pressed to beat the BCM Lightweight Middy with a VTAC/TROY handguard on it. Might as well go with a BCM BCG in it (at current package prices, you buy the BCG and they pay you to receive a charging handle).
The configuration choice would be if you wanted to go 9.0" Rail a fixed front sight, or with a low profile gas block and a longer handguard (11.0 or 13.0) and rail mounted front sight.

I'd just keep your current lower, use it with both uppers. Your RRA upper will make it a great varminter type gun, and the lightweight BCM for all the the other uses.
The ML3 and Surefire would probably move to the BCM Upper, and you could keep the RRA upper with the MI rail sleek.

Daniel Defense will be coming out with their cold hammer forged 14.5" and 16" lightweight (approx .625") profile middy barrels in the next 4-6 weeks. When they come out I believe they will be the only manufacturer that will have a lightweight .625" profile cold hammer forged middy barrel .