Me too, the electric 175 looks nice!
I'd convert the TPE 185s in EMUs and reclassify them as 360/3s. Also, I'd replace the current 360 clusters with the 185 ones as I believe the 185 clusters look much nicer and modern than the ones currently on the class 360.
Also, I'm working on a photoshop that involves a Class 331 and 397 with Chiltern Railways. What if Chiltern Railways was ever electrified?
I would just double the length of all Voyagers and stick a pantograph on them to make them bi modes. Obviously not that simple in real life but never mind.
I would also carry out refurbishments of the interior and try to have as many seats align with windows as possible.
This is what I'd do:
Add a pantograph carriage using a German type pantograph, and use the Class 345 traction motors. As a result, the Voyagers will sound exactly like an Aventra. I would also make the Voyagers 250 km/h capable (155 mph, same top speed as an APT). As a result, the Class 220s and 221s would be renumbered Class 820s and 821s.
I'd also increase the legroom to make them much less cramped.
But, in real life, it looks like it would be cheaper to buy more Hitachi Class 800s than to convert 220s/221s into bi modes.
Do you like my idea of Aventra traction motors in a Voyager?