I had the Oyster (notice I said had). I adored it, I bought it when my little girl was around 9months old. It was everything I needed, it had the functions of a "big" buggy but was compact. However, after 2 months the front wheels siezed - this is a "known fault" with the Oyster - then when it was 5months old I took it back to the shop and demanded my money back...
My little girl naps better outdoors in the fresh air, and most days when I'd bring the buggy back indoors, when I'd take it up the doorstep, it would creak and make fairly loud "bang" noises. A piece of plastic pinged off it from somewhere. The frame became wobbly at the folding joints. I didn't feel it was safe anymore, altho I didn't realise HOW unstable it was until I took it back to the shop and wiggled the display model.
All in all, I loved it but I wouldn't recommend it to anyone. The owner of the shop I'd bought it in told me "quality of this pram was compromised in order to keep up with the likes of iCandy, and to bring out a compact pram".
Sorry this was long, I just know how expensive prams/buggies are and how one wants it to last until the baby no longer needs a buggy.
I exchanged the Oyster for the M&P Sola. I love the Sola, it is suitable from birth if you wanted to research it!
As for car seat... if you wont use it much, it is a lot of money to spend (which could be used for other items). How often do you travel by car? How would you get home from hospital after you have baby? Could you borrow a seat for that journey?