unless you get a spring with a totally wacky spring rate, brand dont matter alot.
currie is supposed to be very nice.
i run re springs cause i tow pretty heavy alot. (their rate is pretty high)
i heard mc rears need quite a bit of bumpstop. (great for down travel, poor for up travel)
i had rockcrawler 5.5" springs on my 2nd tj, they worked good.
i had 4" superlift springs on my first tj for about 100k miles, they worked well, never sagged.
any spring rate between 150 in lbs and 220 in lbs would work fine.
look into teraflex, roughcounty, pro comp, skyjacker, and superlift.
im pretty sure they all offer a 4" spring that would work.
last i saw superlift springs were super cheap!
shocks will determine ride for the most part, unless something it totally messed up.
springs matter very little.
2005 rubicon sahara lj #592