The system that we're running the Waves Ltd. SSL 4000 Collection at the studio is Pro Tools HD based, so we've got the TDM version of this bundle. The computer that we've got to run it on is a very powerful Mac, although I'm not sure the exact specs on it. We've got a ton of analog gear and a Neve 8068 console, so it's definitley saying something that these plug-ins get used a lot. Of course if you have an HD system, you'll be all set with performance, but I can't say how well these would run on an LE system...
If you were going to buy a single bundle of plug-ins for your studio, I'd highly encourage you to consider the Waves Ltd. SSL 4000 Collection. Not only do each of the plug-ins sound amazing, but there's a whole lot that can be done with all of them. Usually you won't find plug-in emulations of pieces of hardware to sound this good, as most of them don't even come close to the original. This isn't really the case with the Waves SSL 4000 Collection, as these sound pretty close to the original although I haven't had a chance to shoot them out. I like the G-Channel plug-in the best since it's the most versatile, but I use the G-Channel Master Buss Compressor a good amount as well, and I'm definitely a fan of all the plug-ins available here. If you've got a studio of any kind I'd recommend trying out these plug-ins, as I think you'll want to add them to your suite as soon as you're able!