Elsenborn Ridge or Battle of the Bulge #1 & #2?

[Michaelangelo]

Good day folks.

I'm hankering for more PG and am considering Elsenborn Ridge; I don't own Battle of the Bulge #1 or Battle of the Bulge #2 - Elsenborn Ridge. My question is this: what is the difference between the games? Does the current version of Elsenborn Ridge include the older games, or do they all contain unique content, (maps, scenarios, counters, etc.)?

I'm interested in Panzer Lehr and recognize that it requires both BOB #1 & BOB #2 (along with Fall of France, Beyond Normandy, etc.)

Thanks!