I'd say PL is just miling their $$ out of the original LPR series.
I tried 1-set of LPR Holeshots; vs. JC Crosshairs (squared up); the LPR's were terrible to drive on. Track conditions were more conducive to the Holeshots working but no dice on the total feel.
They actually tend to traction roll more and are considerably less responsive due to the sidewall flex.
PL VTR, AKA and JC are all about the same width. Pick your compound and tread design and have at it. The newer designs are more responsive and forgiving than the old 'round' design as you call it. Traction and tire wear are improved all around and weight is reduced.
Definitely wouldn't bother with the old LPR series.