the answer to that one is no.
the only way you can get more power out of just sparkplugs is to index them. basically what this means is that they're all facing the same way (firing toward exhaust). I've only watched a part of it, but summit racing has a decent video on how to do it here.
https://www.youtube.com/watch?v=nRo2Cjr66PYas you can see, you basically need a set of indexing washers and a bit of patience. not sure what kind of extra power you would get out of a CA20E by doing this, but back in the day hot 4's did a writeup with dyno results showing ~2kw gains.
Another thing to consider is with the CA20E you have 8 sparkplugs (another good reason not to buy $25 irridium plugs!) and some of the CA20 guys here back in the day hooked up the plugs so they ran at the same time, giving them double the spark. The way they did that is to wire the cable that drives the intake coil to the exhaust coil, causing it to fire at the same time.
You could also have a go at advancing your timing to get a bit of extra out of the CA20 to give you a bit of extra oomph. You're not going to turn the car into a supercar, but you'll at least get a little something extra out of it.