I'm doing a new intake gasket soon possibly (hearing a whistling at idle). Would I get more power with a carb on this thing (93 Suburban)?

 

As a general rule, no.

The GM TBI is just a fuel injected two barrel carburetor. Jack up the compression with a four barrel Holley and it will blow any TBI out of the water. Of course the downside is a carb will run rich at high altitudes, whereas a carburetor has no way of doing that. Fuel injection does.