I'll need to think this through though. I must be part scottish since these investements are always a huge mental battle.
Best of luck with your deliberations, Bjoern. I've had the XP11 demo for a few months now, and am rather impressed. But, like you, I have a stack of add-ons that I don't want to leave behind. Right now, it's Flight Replicas forthcoming Halifax package that's steering me towards getting Prepared v4 rather than X-Plane. The latter's scenery and night lighting is extremely good, however. Its a difficult choice to make.
Dug through the XP web for a bit more. Looks like you can mostly get away with freeware to beef up the weaker aspects of the sim. And Laminar seems to be working on an improved ATC.
I need more space for all this OrthoXP stuff I've got. I really want a high capacity SSD but I've seen sense and gone for a 4Tb HDD at a fraction of the cost.
Almost spot on CB. £85 for a Seagate Barracuda Silver 4Tb beasty. Not entirely sure how I'm going to incorporate it in my case and with all the other drives but I'm sure I'll find a way.
Amazon Steve. It's not the latest version of that particular drive but has more cache than the newest one, is fast enough for a mechanical drive and is quite a bit cheaper.