Sleeves are basically changing the stock cylinder shafts with a percision cast iron sleeve, which is stronger then the stock cylinders.
Closing the deck is reducing / removing the gap created by the head gasket, at least i think..... that one im still not too sure on.

Sleeving the engine is costly but the bonus is all thats needed is replacing them whenever you want, then i believe its just the cost of the sleeves. But it requires boring out the stock cylinder and fitting the right sleeve. In my area it cost about 1600

 

I found a place on the web that installs AEBS sleeves for about $1075. I think that AEBS sleeves are suppose to be the best sleeves you can get, so in your area it might be cheaper to ship the block out to these guys and have them install the sleeves. THey pay to have the engine shipped back to you i think. $1600 is alot to sleeve, unless they do more work than just sleeve the block. I've also heard that H22s have thin cylinder walls that don't hold up under high boost, but i've also heard that this is incorrect.

 

For the most part thats right, you have to keep in mind the h22's have a 90mm bore vs the f series which has an 86mm. So taking into consideration the compression and thinner walls then the f series yeah.... you can blow a hole through there if you have the boost too high, thats why most recommend only 6psi on stock for the h22.
But if i sleeve my engine, i dont have the option to take it apart and send out the block, its my daily commuter. But if i sleeve im going to increase the bore to 90mm and get forged pistons and rods. And the head will be off so that will get ported as well. That wont be any time soon though. BUT if i can get a cam to regrind that and the springs and retainers will be changed out sometime soon. ^_^