Hey Ralph
You could take the easy route (as I did) and have a professional do the job. Even he complained about the difficulty of working in those foot wells. Never the less I ended up with a great job. There is no way I could have come close to the end result, even if I had started with a good quality kit.
Opening up the vents should improve comfort in the cooler months, but it appears to be the norm to stuff a rag in the heater box intake to prevent the hot air from flowing in the summer. Wish there was a cost effective way of improving that situation.
Ed