50/50 weight is in my opinion always most important, especially considering the center of gravity is already fairly low on an xtreme. shocks and springs being properly paired is right up there though. currently it is a bit tough sledding to pair new oem z87 shocks and zq8/z87 springs due to availability or whatever... there may be better options than the oem-z stuff though, i would just imagine that you will be paying big money for negligible gains though.
do you have somethin hiding under that there shaker ya got there? most are just for looks and i agree that it does look better, that hood does. i always planned to get that one but here i am with burned up clearcoat on my stock hood and just planning to re-paint it come spring...
i cant remember exactly but i vaguely recall reading that blazers were close to 50/50 weighted stock depending on the size,location, and mounting mechanism of the spare tire... dont quote me on that though.
sadly you may well be better off throwing more money at your motor at the moment (if stock)... i would imagine electric fans will be an easy power gain if you havent already been there done that.
nice lookin blazer regardless