I've just fitted a 2 inch 4 hole plastic spacer. I'm waiting for my driveshaft to get fixed next week and then I'll let you know how it goes.
Only thing is I've fitted a 2.5" twin exhaust with 4:1 pacemakers at the same time so I won't be able to tell how that mod worked by itself.
Here's what it looks like. Haven't heard of the "super sucker", but in general from articles I've read, they do improve TQ and HP. Not by much, but 5-10hp for $15 bucks is a good return.