-200's your on drugs. Haven't even had 300's for years. The IFE in the 400's is crap but what do you expect when they will be gone soon.
As for performance issues not alone in that department. QF 737s had issues with de rated 800s going into places.
Which would indicate to the QF performance guys that there would be no restrictions even with 18.5k engines.
Why is QF performance doing things for Cobham?