Be sure to check out the post at the top of the Forum to guide you around some serious pitfalls installing, running and adding patches to RB3D!
HASP (and latest FM) with either the "OTE/combo" terrain(at the HASP site under "Scenery") or
will give you the quickest full upgrade, some Bomber types have been replaced.
For a completely STOCK plane upgrade, HAGOLD is available. Some people chose this because there are many, many FM's available.
Both of the above terrains also contain hundreds of updated graphics files like fire, smoke, sky and more, ensuring a complete graphics upgrade for the game.