Not only they work very well, they very well ESPECIALLY in P3D V4. A thread here on Avsim P3D forum, with some very positive comments about how well it performs on P3D V4:
https://www.avsim.com/forums/topic/523526-anyone-here-buy-fsdt-louisville-well-how-is-it/So, it's clear that what you mistakenly labeled as a "disaster", as if it was common knowledge those sceneries (available in Trial, so everybody can see how well they work, we do not hide anything), doesn't have anything to do with the sceneries themselves, which instead are very well known to perform very well, especially in P3D V4. Even considering you say you also have KCLT, and both KMEM and KSDF are quite similar to it, in the way they are made.
Had you said you use FSX, I might understand there might be some critical issues, and there are tweaks to reduce the performance hit on FSX. But P3D V4, sorry, that's not possible and, whatever problem you have, it doesn't have anything to do with the sceneries.
Now, having said that, you don't even SAY which problems you had. Again, maybe you assumed it was common knowledge they have issues in P3D V4 but, since this isn't obviously the case and, in fact, common knowledge is exactly the opposite, could you please indicate, exactly, what problems you are having with them ?
Of course, I've edited your unfair and very misleading "Wasted $57" thread title.