Alright, I'm only going to say this once so listen very well..... I see all of these other threads you're already looking for a vito's kit, a LA sleeve kit.. blah blah blah blah.
NO ONE can tell you what mods YOU need. There are many factors to consider here.
#1 your power goal. If you're drag racing, obviously displacement is first place so at any costs, you'll set it up. If you're trail riding top end HP isn't where it's at, you want a nice broad power output
#2 your budget. If you have an unlimited budget, you can buy whatever you want, the skies the limit. If you're working on a reasonable budget of a few hundred dollars, you can't buy a BBK (sleeve or otherwise) AND the supporting mods. You're better off getting a port job and pipe than buying an unported vito's or sleeved kit and not being able to get anything else.
#3 your eventual plans. If you PLAN on building a ridiculously powerful blaster in the future (max POWA) then the displacement will come into your favor. You'll be glad you bought a BBK later but that only applies if you can eventually see yourself going after the absolute maximum power possible.
Only you can factor these things out and decide.
Personally, I like the idea of buying another complete top end to replace yours and selling yours (if it has any life left in it) to help offset the cost. Sleeving also doesn't add any more material around the exhaust port like a vito's or LA sleeve kit (the vito's is NOT an exact copy of a stock cylinder, you just can't easily see the difference) so exhaust port timing and area are limited.