[Klemm]

Are the mods 4.09B compatible?

Also, I would like to see a mod that gives the right aircraft the right performance at the right altitudes. The Me262 struggles to stay above stall speed at only 15,000 feet.

Absolutely. Like the Ta 152 H, with which the other day i couldn't even reach 12000 Meters with engine on max and boost enabled. or the Me-262, which struggles to stay above stall speed at 30000 feet (not 15000 lol), it should be easily climbing at even 11000 to 12000 meters.
Altitude performance is sooo off in this game. But i suspect that this is due to a serious flaw in the FM of the whole game, like most planes have the right speed at one altitude and the wrong speed above and below. And the FM seems to be pretty complex and linked to various parts of itself, making adjustments in one region affect others. So i fear that if those aircraft's FMs were adjusted for up there, they would be just wrong in the lower altitudes.
Just my 2 (