Marty, with the recent ATF ruling, you cannot add a pistol brace to this firearm without paying a $200 tax and registering it with the ATF, as adding a brace would turn it into a short barrelled rifle. If you want to go that route, DoubleStar’s pistol buffer tube is compatible with popular arm braces on the market, no modification needed. As to the 2nd part of your question, you cannot add a vertical foregrip to a pistol without turning it into a AOW (any other weapon). A pistol is intended to be fire one-handed, by adding a foregrip, it is now meant to be fired with 2 hands. As with the first part of your question, this would require a $200 tax stamp & registration. Again, if you wanted to go that route, you can use any vertical foregrip that is M-Lok compatible. Have a great day!

Marty, yes you can add a pistol brace without modification using the buffer tube. Unfortunately with Bidens new pistol brace ban all pistol braces are now basically classified as a stock and would make the pistol a short barreled rifle and require a lot of paperwork and a $200 tax stamp. They're still fighting to overturn this new rule but that'll likely be awhile and until then adding a brace to a pistol requires it to be registered by the ATF. As for a pistol grip you can add a angled foregrip or handstop but not a vertical foregrip. A vertical foregrip would also require a $200 tax stamp. The handguard attaches accessories using mlok, so any mlok angled foregrip/handstop would work. If interested here's a angled foregrip that would work and not require a tax stamp.................. budsgunshop.com/product_info.php/products_id/714022816/utg+ultra-slim+angl+foregrip+mlok ................... Or here's a link to a mlok handstop that would also work................... budsgunshop.com/product_info.php/products_id/110264/sig+sauer+kittrdgriphandstopblk+tread+handstop+kit+black+polymer ................... Unfortunately there's alot of laws when dealing with a AR pistol, those are the two main ones. Sorry but hope this helps.

Hi Marty, unfortunately you can't at this time until the ATF Pistol Brace resolution. You cannot add a vertical grip without NFA Registration but you can add an angled M-LOK grip of your choice without any such NFA registration and be perfectly legal from here : budsgunshop.com/search.php/q/angled+grip. Cheers and stay safe!