As I mentioned in my original post, everybody would use a different manufacturer for different reasons.
As a DIYer your going to get limited support, no matter what product you get, many come without installation manuals as they are aimed at trade only.
While we are all chipping in I'd fit an Elite 48 with whatever extra modules you need, in fact did exactly that last week 9800 for a PE48.
The cab is 3inch taller and half inch wider, so fitted great over the hole in the plaster where the 9800 cab came out, if that's a concern.
As for the wireless side, one way means the detectors spam a messages to the panel in the hope they are received.
Two way each message is confirmed to be received between the detector and the panel.
Texecom is mesh which is two way with the added benefit of messages can be send via other detectors.