Admin
I would like to upgrade my ignition system in my SW20 and retain the distributor (for now).
What value are you aiming to get out of doing this?
Admin
Can I retain the stock ignitor and use an aftermarket coil?
Yes.
Admin
Should I replace the ignitor as well as the coil?
If you are on a stock gen 2 (your sig says ct26), then the igniter is also the ignition computer. You have no choice but to retain the stock igniter. If you are having hesitation or missing issues it is an easy one to change to see if it helps, but generally if there are problems with them it's usually fixed by cleaning contacts/fixing wires.
Admin
What brand is recommended? I have been considering MSD.
MSD's coil is well known among the MR2 community to work quite well, but you do need to modify the ignition leads, this is not difficult.