Hi,
Yes, a high-torque/gear reduction starter might be the ticket, giving better starting ooomph along with much smaller size and ease of installation. I'm not sure about using one with the earlier, press-on ring gear Geo refers to, though. Better investigate that. Try
www.britishstarters.com
Another concern is if your car has a high port or low port head. Some early TR2/3 heads have all the ports lined up (called "low port"), while the later have an alternating high/low arrangement of intake and exahust ports (called "high port"). Headers for the later heads are much easier to come by. Headers for low port heads might need to be custom made.
Other considerations...
Headers will add to underhood temperatures, since they pass heat more easily. They will also add some noise.
Due to the greater radiant heat from headers, heat shielding is highly recommended for any nearby items that might be effected: starter, carbs, generator, fuel lines, brake lines.
A possible solution and alternative to shielding is to wrap the headers (a newly-popular, old idea borrowed from 1950s hot rodders and drag racers). In order to be fully wrapped (100% coverage), a header should be stainless steel that will be more expensive.
A mild steel header can be wrapped with only about 70-80% coverage, or it will corrode much more rapidly. A better alternative with mild steel might be to have the header ceramic coated. This can even be done to rejuvenate a rather ugly, but sound, used set of headers. Check out
www.jetcoat.com
Wrapping or ceramic coating will both effectively void any warranty on a new set of headers.
Headers are a good, bolt on performance upgrade, done right. The late, TR4A dual pipe exhaust manifold was actually pretty good... but replacing earlier manifolds with headers will give more noticible improvments.
Your carbs might need rejetting or tweaking after headers are installed, since gas flow will increase and the engine will breathe more efficiently.
Have fun!
Cheers!
Alan