OK..... I've exhausted all other sources.... Should I get a mini uzi SBR and re-chamber in 357 SIG or a Sig 556 pistol with a stock?

Uzi is small and cool but still just a glorified pistol. The sig is a rifle caliber but quite a bit harder to conceal.

I want to be able to conceal and car carry a shoulder fired weapon.

Please offer up your opinion.....