I currently own Heresy 2's,KG-4's,Short Horns & K-Horns , ive owned Heresy 1's,Cornwall 1's,Cornwall 2's & most likely a few others if a really think about it.
As long as all the models are up to spec with no leaky or dried out caps in the xover system ,or damaged diaphrams in the horn drivers all 3 models will sound the same or very close,not much has changed with the Heresy in 30 years ,which is a good thing.
Others over at the Klipsch forum will argue what ive said to death,reporting so many differences between the models it'll make your head spin,i cant hear big differences when i compared them.