I still see a lot of confusion about Acceleration ( aka X-Pack ).
X-Pack is an expansion pack for FSX. X-Pack contains the following new features:
1) F/A-18 (military jet),
2) EH-1O1 (helo),
3) P-51 (racer variant)
4 systems upgrades
1) Carriers (tailhook, arrestor, catapult, launch bar, meatball)
2) helos ( true multi-engine, hoist, sling loads )
3) Racing engines (ADI, failures)
4) Racing system (gates and laps, counters and timers)
5) Reno (for the Reno air race)
and most might have missed it, but the area around Mt St Helens (for the rescue mission) now uses 3M LIDAR data exported with custom fraction bits to enable smooth mountain meadows instead of the usual stair stepping.
Plus the X-Pack installer automagically detects and installs both SP1 and SP2 as required.
For those of you who do not remember, here is what is in SP1 and here is what is in SP2.
X-Pack contains a lot for $30.