I love this scenery and pretty much everything from Glenn Johnson. It's not bad on frames and it looks sooo much better than default. Keep it up, Glenn!
OK, so what it does is this: 1. Adds terrain shadows (which is a pretty cool addition). This is unique because the standard Terr button just shows different colors to represent geographic features. This has shadows and simulates actual terrain. 2. Adds TCAS. The nice thing about the readme is that it tells you how to modify the TCAS information. You can either have "standard/realistic" TCAS symbols, or you can have (unrealistic) larger diamonds with the traffic aircraft's track noted.