Top of my list would be aircon. Then adjustable lumbar support for my knackered back. Power steering for all models, plus a beefed up five speed box to handle power. Twin cam heads would be good (don’t know what that would do for engine characteristics though). I think the round instruments are the best I’ve seen on any car bar non, so they should be retained. Efi and related bits to make it more reliable/less juicy. And if we’re talking about a new 2017 car, a little sympathetic attention to the exterior lines which at the moment are delightfully 60s, and some details of which do show their age. I’ve never entirely liked the rear lights standing tall as they do, I think the line loses a little aesthetic beauty here. Redesigned rad grill, maybe some mesh in there to give aggressive cues. Keep the engines but engineer tha weaknesses out of them, eg v8 camshafts. Silence the four cylinders a bit, while keeping that wondrous exhaust note, and make the v8s exhaust note a feature to amplify slightly that v8 burble. Make base units in stainless with ally panels for no rust. Dual braking with abs and airbags. Keep to the spirit of the original above all, that of an older car which was more visceral - you can feel the engine running and hear it too, and everything has a machine like feel - gear selection feels like a rifle bolt and you can feel the mechanism beneath as you use it. I think this would be a p6 in the same way that Saab did with the 900, or that Porsche did with the 911. Development and evolution while keeping essentially the same car.