Nice set up. Did the Backpacker reduce the weight of the carbine?
I was going to add an extended mag release and bolt handle and decided against both. Too easy to bump the release with an extension. I have considered adding a heavier spring to the mag release but I haven’t researched that yet.
Just to add to what Jonah77 posted, per Ruger's website, the standard PC Carbine weighs 6.8lbs.
https://ruger.com/products/pcCarbine/specSheets/19100.html
The Magpul Back Packer stocked one weighs 6.2lbs.
https://ruger.com/products/pcCarbine/specSheets/19130.html
I find the balance to be a little better with the Magpul Backpacker stock (MBs). Also I like the butt plate on the MBs as it doesn't snag on my clothing when shouldering the rifle, like the standard rubber butt plate does.
M*Carbo offers a whole bunch of bits and pieces to "upgrade" the PC Carbine. However, my recommendation is to shoot it as is before buying any "upgrages." Other than the stock, I like mine just fine as is.