Has anyone ever heard of someone upgrading the starter motor on a high comp a series?
Does the standard slug have the required torque to turn such a beast?

The original 1200 starter is a bit weak. The newer Mitsus are hi-torque. The Bosch is good.

But the real cookie is the factory reduction gear starter.

See wiki - Starting Motor

so am i right in saying that the sunny a15 starter would be much better than the 1200 a12 one ?
would a c20 a15 starter be better ?

my educated guess is that a 1980 A12 starter is better than an 1973 A12 starter -- not because of age, but because of design.

The A15 and A12 use the same starter.

ohk well that sucks then. so im looking for a later model a series then, b310 ??

Check the wiki, it has links.

For 11:1 I see no problems, just use a good battery. For 14:1, I dunno maybe ask the drag racers?

I had 11:1 and my starter worked fine with good battery charge

i have 11:1 no problems at all

12.9 struggled alittle
Make sure you have nice fat leads

The gear reduction ones are quite nice not very expensive, less than $150, but now days, you can get a decent rebuilt regular one for $35 so it's a bit more. I had one, it was ok, the regular ones seem to crank faster, which was better for my app, since the GR one was requiring a lot of cranking to get the gas going in the morning, but that's particular to my app.