You can use the first Spark hardware with Spark 2. It includes an option to use the old hardware interface (or the new). It includes all of the original content of the first Spark version along with new content. I am not certain if it officially includes all of the Spark Vintage Drum machines now or not, as I've acquired many extra kits over the years.
Take notice of the threads about the lack of recent updates. There are still some bugs, but its easy to use and quite capable of producing drum trakcks. There's only one bug that really annoys me....