I have the Xenon Depot 35W HID kit with 5k bulbs too. I haven't noticed any change in color or output from new till now. It's interesting your kit did not include the additional relays mine did. Although I could have installed the kit without the relays simplifying the install, Xenon Depot strongly recommended I use them. They're there to provide an additional layer of protection for the stock electrical system. On the mounting of the ballast, I chose to use some double sided tape and mounted the ballasts under the headlight assembly. There is a space under there which works perfectly for this and helps contribute to the stock install look I wanted to achieve. I'll take some pics of my install and you'd be hard pressed to know something aftermarket was installed unless you know exactly what you're looking for. Certainly a lay person wouldn't know.
As for the bulbs, they don't seem to be mounting upside down. Xenon Depot says they're Phillips sourced bulbs.
I've been saying for anyone who owns a C-HR, this mod should be the very first thing you do. I'm not talking about having a look in terms of the light the headlights produce. I'm talking about overall safety. The stock halogens are terrible and I would say is a safety hazard as you can't see much of anything with them. Even with the high beams, they were abysmal. The HIDs make a huge difference in the amount of night visibility you have. For those that haven't experienced a recent/modern lighting system (HID or LED), you won't appreciate the huge difference until you actually experience it.
2019 Toyota C-HR LE Silver Knockout Metallic
2013 BMW 135i Carbon Black
2009 Ducati 848 Pearl White/Black
2004 Kawasaki Ninja ZX-10R Black