You know, I read many reviews about trying to get Jetfire's engines in place, and I've never had trouble with mine, and mine LOCK in place very firmly. Either I have a marvelously better one, or everyone else is doing something wrong.
As for a chromed-feet Prime----mine's never chipped, but I've also almost never had it on a hard surface.
Man, I'd love to get the 2-pack, but just can't afford it now. (maybe if I sell my 1st-movie chromed Prime and US Jetfire, but they tend not to have any buyers with the better versions out now)