Most Torrent clients should allow you to specify which ports to use. Personally, I use BitTornado and forward ports 6688-6999. It isn't near as my as your ABC client says to use, but I never have had an issue with mine. My client is almost always able to find a seeded 'greenlight' torrent and finishes without problems.
No, I wouldn't forward that many ports...that's a LOT of ports to open up. Who knows what spyware/malware might operate on those ports only exposing your system to the outside unknown!? :Q