Porsche Design info

I've recently bought three pairs of sunglasses from this brand. I really like the style and I've been able to buy them from authorised resellers at substantial discounts from the (admittedly artificial and inflated) MSRP's.

I'm no expert, and I certainly don't have the knowledge to speak to the lens quality, but the frames appear to be built to a high standard. They are several notches above any frames I've handled (mostly Luxottica, admittedly) in the sub-£200 range. They are also very lightweight and exceptionally comfortable. The only thing I'm less keen on is the size of the logo on the lenses. But you can't have it all, I suppose.

One thing that caught my attention, is that two of the pairs I own, the P8967 and the P8923 are discontinued models (at least, I assume so - they don't appear on the current Porsche Design website) and they are stamped on the temples as being made in Japan (incidentally, both these models are titanium frames). However the P8964 is a current model, is stamped as being made in Italy and is made of a combination of (non-titanium) metal and RXP (fancy plastic, as far as I can tell). My initial assumption was at some point in the recent past, the actual manufacturer changed. It looks like the current manufacturer is De Rigo. On reflection I wondered if the company uses more than one manufacturer depending on the frame?

I've found very little information on the brand looking online, including on this sub, beyond the generic corporate spiel about the brand's origins as an idea conceived by Ferdinand Porsche and so on. So I'm curious to hear from anybody who knows anything about them - particularly the switch from manufacturing in Japan to Italy - and what your opinions are. I'm also curious if there are any actual experts who can speak to the lens quality. And finally any owners who have any opinions on their glasses?