In answer to the question regarding "can I start the engine with key alone?" , the answer is at this point in time I don't know. I'm fairly certain that the answer is "No" because when I bought the car it only had one functioning fob and key. In other words I had a spare key (and possibly a fob but that fob either needed a battery or re synchronising). The key itself would enter the petrol cap and possibly the door or ignition but not both and not the boot. After a bit of grinding and use of a file I removed some more metal and it would enter all locks and operate each one (but as stated without the fob no engine start as far as I can recall and there may even have been an alarm if tried (but it is a while back now).