Theres so much info on here about spam and how to beat it, If you do a search you'll come up with some brilliant articles and posts.
Different members have different ways of dealing with spam, and each has a story to tell.
Another tip is don't let the differnce in mod versions put you off installing a spam mod, Many spam mods working on 3.6 will also work happily on 3.7 and 3.8 Try it and see.
Personally myself the best hack for stopping spam on my forum is the "Is Bot" mod, That alone stops 99.9% of bots and works a treat for me.
I wonder if anyone has started up a Viagra and Porn Marketing forum, I bet they would get 1000's of sign ups daily and a very busy forum


Good Luck buddy with your fight against the Spam, But all the help and info is here, ready to be read
https://vborg.vbsupport.ru/search.php