Does downloading PC games off torrent sites have a high risk of getting harmful viruses or spyware

No higher a risk than downloading anything off any random site. The two main risks in getting a computer viruses are suspect files from untrusted sources and malicious code inserted into web sites that take advantage of vulnerabilities in web browsers/operating systems.

While there are many scam torrent sites out there, take some time to find legitimate torrent sites and read the comments on torrents. Usually if there is a problem with the file, the users will comment on it.
EDIT: Also some seeders might insert their own viruses into the games they seed, i had an incident when my friend got a setup from a torrent and had trojans burrowed in.