What's the difference between a dump launch and slip launch?
 

I am going to take a crack at this...

DUMP: Put the gas to the floor and it will bounce off the rev limiter... then you just take your foot off the clutch

This will probably reslult in a drivetrain SLAM? Causing expensive stuff to break

SLIP: Gas to the floor and it will bounce off the rev limiter... then you slowly let the clutch out until it grabs but it will slippp a bit. Almost as if giving too much gas when turning and the clutch wasnt out all the way...

= not good for the clutch, not aweful but much better than just rev+dump = all the power has to go somewhere? Can someone fill me in?

dump foot on gas let off clutch as fast as you can...breaks everything

slip, foot on gas, slowly take foot off until it starts to grab, than swiftly take it off. quick and precise is key.

wear aside, a "dump" launch will be slower than a proper "slip" launch. You should have much less wheelspin and get off the line alot smoother and faster.

Does this hurt the car still? And how much?

Start reading up on how to change a clutch...

And I found on my IX that the stock clutch couldn't hold a full throttle launch. I had to feather the throttle or I'd get clutch slip all the way through 1st gear (as in 7k on the motor until the car caught up). My ACT doesn't have that problem.

Ok this is where I am assuming the "stock clutch sucks" part comes in. Does an aftermarket clutch replacing the stock one usually mean that it is no longer an issue?

well a clutch is still no more than a plate with lots of friction material...so it will eventually lose that the more you slip...more so if you are doin it incorrectly...but people have attested to 100's of pulls and drag time on there cluthces and its still holding...

practice all you can now on the stock clutch and have the other ready to go in...its a pricey thrill

You'll still burn through clutches if you're launching the car all the time. You can just launch at full power as opposed to having to hold back to get the clutch to grab. Of course, if the clutch is no longer the weak link in the drivetrain, something else has to give, and it won't be the tires. Usually it ends up being some very expensive mechanical parts.