Thanks, Doug. That's what I though - coil has to be under 'load'.
(In Canada the penny has been taken out of circulation...)

Hi Dan,

The purpose of the penny is to make sure the points appear closed even if the cam has them opened to their max gap.  You want to have current flowing through the coil during the voltage measurement tests so using a penny is just an easy way to insure that happens.  You could also turn the engine over until you visually see the points are fully closed or you could use a jumper wire between coil (-) and earth to achieve the same thing.

Doug Lawson wrote "Remove the distributor cap and put a penny between the contact points"

Doug:
Can you clarify - do you put the penny between the contact surfaces of the points to ensure electricity is conducted or betweew the points and cam to hold the contacts open?

Am I that predictable?

As Malcolm said, the coil you need depends on the car.  There are visual clues but since you have points, I suggest a quick voltage measurement.  

Remove the distributor cap and put a penny between the contact points.  Set your meter to measure volts (0-20v if it is not an auto-ranging meter).  Turn the ignition key to the run position and measure the voltage between coil (+) and an earthing point... like the alternator/generator end plates or a cylinder head stud.  Record the voltage, switch off the ignition, and remove the penny.

If you measure 12V, you need a "standard" ignition coil (typically 3 to 4 Ohms).  If you measure 6V to 9V, you need a ballast ignition coil (typically 1 to 2 Ohms).  

There is not a lot to be gained by installing a fancy coil while running points.  A high voltage output performance coil will only offer marginal improvement until you fit an electronic ignition.  The on/off switching of the electronic modules changes the effective dwell which in turn allows you to increase the spark plug gap a bit... and that allows for a hotter spark to be produced using a performance coil's higher output voltage.  I am a fan of Bosch Blue coils for use with standard ignitions using points.  However, do your homework.  Not all Bosch coils sold as "blue" are the right ones.  You want the ones from Brazil.  They may be available from our host.  They are definitely available from Jeff at Advanced Distributors. 

It would depend on what voltage you have at the coil currently. Some Mini's are run with a resistor in the wiring harness and the voltage is reduced to 9.5 volts, others are a full 12 volts. Before upgrading the coil if you are thinking of getting rid of the points you should look at the electronic ignitions available and buy a coil to match that set up, some are even sold as a package. Doug Lawson will hopefully chime in.

I have a 998 JDM Import with dual HS2's and a stage 1 kit, the ignition has the stock distributor with points.
I'm thinking of upgrading the stock coil which looks a little worse for wear  but I'm seeing many different options 1.5 ohms, 3ohms, 42000V etc. 
What's the requirements for a slightly-better-than-stock coil?
Any suggestions?

Thanks