Last summer I was practicing launching in my 08 6mt, I could get rolling without a lot of slip but once I got above 4000rpm in 1st I would start to slip, regain grip, slip, grip, slip, all the way to 7000ish. This felt really unpleasant, almost bouncy. I generally avoid doing unpleasant things to my car, so I avoided doing this after that time. It was not a smooth burnout or anything (what i expected to happen with a lot of power).

Now that its snowing, I decided to see what would happen with VDC off. After getting moving and releasing the clutch fully, I got that same bouncy, alternating feeling. I always figured I'd just get the rear wheels spinning in the snow if I got into the power, this clearly isn't the case.

My question is, are either or both of these situations wheel hop? I've generally read wheel hop is bad, but don't quite understand the dynamics of it. What I feel is grip, slip, tires regaining traction (due to heating up?), grip, slip, tires regaining traction....

 

"Wheel hop" afik is a general term to describe what your're talking about, regaining and loosing traction over and over under acceleration. A few things can cause it (others feel free to chime in here, I'm no expert) including being out of alignment, having a suspension that's too stiff, and having incorrect tires (usually incorrect for the temperature).

Best advice, if it feels bad, don't do it. This engine generates a heck of a lot of power at high rpms, in first just feather the throttle a tad until you don't get the hop.

 

Starting at about 1:27 of this video you can see what wheel hop is.
<iframe width="640" height="480" src="http://www.youtube.com/embed/o1SSIGSTPBo?rel=0" frameborder="0" allowfullscreen></iframe>



Also it is very evident on this drag launch.
<iframe width="640" height="480" src="http://www.youtube.com/embed/DHlEWHJ-o2w?rel=0" frameborder="0" allowfullscreen></iframe>

A picture is worth a thousand words.