High flow cats on stock LT4
 

My car is stock and I am considering replacing the old, OEM cats with new high-flow ones. From what I understand the high-flow cats of today would outperform the mid-90s designed cats currently on my car. Is this worth doing or is there no benefit gained?

I don't think that there is anything to be gained. Take a look at the physical dimensions on your LT4 cats and then look at the aftermarket "hi-flow" cats. The only time people with late model LT1s or LT4s change to aftermarket cats is if they replace the exhaust manifolds with long tube headers and the collector then sits in the area previously occupied by those large cats. Then you go out and buy some "hi-flow" bullet cats from someone like Random Technology.

The dual exhaust on your LT4 is generally considered to be nonrestrictive up to about the volume of exhaust needed for 400RWHP.