CRX injectors...

Besides the stock injectors, are there any other injectors that will thread into the stock manifold that would better performance? I'm replacing the injectors and I'm wondering if I should do an upgrade now. Thanks.

I wouldn't swap the injectors without also swapping on a bigger throttle body. The reason for this is because if you only swap in bigger injectors your car will just run rich. But if you balance out more fuel with more air, then you will see some power increase. You can use the injectors and TB from an '86-'89 Integra D16A1, though you will have to construct an adapter plate in order to bolt on the throttle body. There are no adapters available anymore and there are no TB's that will simply bolt on. If you go to all this trouble of swapping parts, you should also consider swapping in a bigger cam in order to take advantage of the other swapped parts. If you need injectors now, you'd be better off with stock replacements. Later, after you have the throttle body and camshaft, you can install an adjustable fuel pressure regulator and increase the pressure for more fuel which will give you the same effect as bigger injectors.

dont run bigger injectors even with a bigger TB, the map sensor will just pick up an incrase in manifold vaccume and adjust the fuel injectors to dump more fuel. if you want bigger injectors you will need to be able to program them.

Will the cam from the D16A1 bolt into my D15A3? Will this offer any improvement if I also use the TB?

Not at all. The heads are no where near the same.