So I did it, and to tell you the truth, I'm not too impressed. I didn't really feel any change in power or smoothness, although the engine felt like it was breathing a little better. I guess that's a good thing. But I was really expecting more; maybe my motor didn't really need much, as others swear by it and say they saw a lot of improvement. I ended up putting the whole can into the intake manifold via the brake booster inlet, as you can see in the pic:
The car never stalled, but it was having a hard time staying alive. Then I shut the motor off waited about 15min, then started it back up again. The video here is with the car at idle, and you can still hear it struggling. Not much smoke as you can see, unless you rev the engine:
I don't think the experience is worth a DIY, since the directions are pretty clear on the can. It'll tell you to use only 1/3 of the can through the manifold, but I, as well as some others I've read about, used the whole thing. It smoked for a good half hour at idle, with a little revving here and there. Then I took her for a test drive, and she smoked a little more. Your experience may vary, remember catalyst said his was smoking pretty heavily.