New to SBR's

General Firearms NFA
1

I was looking into building my first SBR, and I was wondering if there are any reliability issues with using the DI system on an SBR? Say 7.5 to 11.5

Should you use a Gas Piston design with an SBR or will a high quality DI work like LMT or Colt?

Also, it would be for S/A not F/A

And does having a suppressor effect things like bbl length, or the need for a Gas Piston?

Thanks