The SSL should allow sites to access to the API when they are forced via a transparent proxy and blocked due to abuse. I'll add the ability to run API checks on port 8181 (http) and 4343 (https) shortly for those sites behind really annoying provider gateways.
To use SSL in the API, you will need to edit the plugin and change the query URL from
http://www.stopforumspam.com/api
to
https://www.stopforumspam.com/api