Ok guy's, while i'm learning more each day, theres still a lot i dont understand, and can get quite frustrating..Listed below is what i've done so far, but something still isnt right..

New spark plugs
New plug leads
New oil filter
New fuel filter
Changed oil
Flushed radiator, and topped up
New battery
New engine mounts
And service trans (tommorow morning !)

But it still doesnt run right, it runs good, but it's definately not %100. It has a slight missfire at idle, which i know is affecting it, and i dont know what could be causing it. I've been told, yeah just needs a tune. But what is a tune on an EFI car? will this solve the missfire, or could it be something quite serious? does it have to be plugged into some sort of computer or something to diagnos a missfire? sorry if that sounds silly, but when it comes to the computer ect side of the car, i know absolutely nothing about it...