Welcome. This BB has some great information, dating way back in the day when the core members were experimenting with all sorts of things. This was because unfortunately, a large aftermarket never developed for our platforms so we had to improvise as best we could. Over the years, there have been some advancements but with the platform's discontinuation, things have pretty much leveled off and we are back to finding interesting and unorthodox solutions.
The site however is not very active day-to-day. Most of the daily posts about pretty much anything are now on the Offroad Trailblazers Facebook Group -
https://www.facebook.com/groups/offroadtb so you may want to check that out and see where things stand right now.
As for your question ...
If you are talking about the front control arms, there is nothing but stock replacements from the likes of AC Delco, Moog, etc. There are some heavy duty ball joints available now however, they are the TTX line from Mevotech:
https://www.mevotech.com/part/TXK6664https://www.mevotech.com/part/TXK6663And there is a Prothane poly bushing set available for the front as well:
https://www.summitracing.com/parts/ptp-7-242If you are talking about the rear control arms, there have been and are upgrade kits.
Spohn makes standard and adjustable upgrades:
https://www.spohn.net/shop/2002-2009-Tr ... uspension/And Massive Speed Systems makes adjustable upgrades with upgraded joints as well:
http://www.massivespeedsystem.com/suspe ... 10038.aspxGood luck on your mods.