Balance advice:
This missile has between stingray and avalanche range, being able to outrange most alien craft. Its total damage throughput is lower than avalanche, while stingray is higher than avalanche. These missiles aren't as large as avalanche but are still a bit of a space hog. Compared to vanilla missiles, I'd say their range means I'd definitely want to use them over stingrays most of the time, while the lower damage throughput means sometimes stingrays could be useful. I wouldn't pick these over avalanche even given the smaller size. They're less powerful and with less range.
Just offering comparison to vanilla weapons.