So this morning, I get into my MINI and start, get into first gear, 'check engine light' comes on and the RPM drops to well below 1000 and the engine is shaking vigorously. I was driving it fine last night. I've never encountered a misfiring before so are these the correct symtpoms?

 

Check your spark plugs and spark plug wires. I have had Iridium plugs go bad with as few as 20k miles. You didn't mention how many miles on your MINI, nor if you have any mods, MC or MCS, etc. Give us a bit more detail and maybe someone can offer more constructive advise.

 

I have ~42500 on a 2002 MC, just bought it from a private seller who did have the dealer check it at 40000, the ignition wires were replaced, no mods whatsoever

 

Replace the spark plugs if not already done, 40,000 is enough mileageto get some wear. Also check that plug gap is within tolerance. I'll have to check my Bentley's for the gap, as I don't have it memorized for an MC.

 

The proper plug is NGK BKR6EQUP (part#3199) it is a multi ground and does not need to be gapped. Use a small amount of silver anti-sieze on the threads, and torque to 20-22 ft.lbs.
Cheers,
--Dan

You could also have a coil problem, or some bad fuel.