Here's a pic of the blocks that come with most lift "kits" - it sits right over the old spring mount and the old spring sits right on the lip ...
20121007_093747.jpg.jpg
I had fears a couple of years ago as to the structural integrity of the setup as the spring just holds itself in place, but my cart has been rolled, flown, folded, spindled, and mutilated many, MANY times since then without a hitch
Also - if you look at 1fast's pic, you'll see the shock extenders that come with the kits - in my photo, you'll notice the shocks go all the way to the swingarm ... Those are the Monroe 31000's, in addition to doing WONDERS for your ride, they also eliminate the noise and instability that the extenders contribute to. This last kit I bought I was able to finagle a deal on as I only needed the lift blocks and spring risers (none of the extenders or associated hardware) because I am installing Monroes all around ... at around $15-17 per shock, it's a HUGE investment that won't break the bank and believe me, I would never think of lifting another Marathon without going the Monroe route