If you had the old SAR8 and sold it, big mistake. The current SAR8s are worn out parts guns on Federal Arm receivers.
Pretty much ALL US receiver guns suck.
Only option to consider is a FMP (HK contract) receiver and a NEW (not like new or refisnished but actually NEW) HK part kit built by a real HK gunsmith.
There are only about 3 REAL HK smiths out there and only ONE who will work on contract guns anbd that is Jim Gravitt.
We weere building and selling these guns(well Jim did the building part) but they can run about $1,600.00 and a preban German is only about $300.00-400.00 more.
Granted the preban won't be new but most people will spend the extra few bills for preban German.
But all the $400.00-$900.00 clones are nothing more than unproven and usually out of spec US receivers and parts kits of varying grades from well used to retired 10 years ago and hit with a fresh coat of paint. Don't waste your cash.
Either get a preban original or do a kit gun the right way. Or just get a DSA FAL.