i like them . quality is great , and they seem beefy . the lowers are thin wall rectangular tube steel but thats needed for roll when you drive over something on one tire just as it is with the stockers, but they are square tube so they dont deflect like stockers .
if your stockers are in good shape the poly bushings and the boxing the lowers can do the same , i just sought an easy swap that wasnt much more $$ than doing the boxing bushings ,even if i was doing the welding . i had a pinion angle problem due to frame issues so the stockers werent going to work and adjustable was the only way to go for me .
with the hiem joint the uppers arent in any way bound as they can rotate at the heim fitting .
wish i could have had lowers built similar to the uppers (frame end heim joint ) even if they were still fixed length so the sway bar coulds be retained and to allow for more unrestricted roll on them (help to prevent bindup which can cause unpridictable breakaway under power in the turns ), they offer adjustable heim end lowers but you need to run something like the hrpartsnstuff bar or the wolf style race bar (they sell them on ebay) .
i do find i need to tighten the bolts on ther lowers up every so often so i may do something to keep the nuts tight (like double up with another nut) and they did need some time for the grease to get worked in (grease them before install will help), otherwise all i notice is no more axle wander and much less front roll
i dont do a lot of miles on the GN and i not going to go to all out drag race setup ( tall soft wall tires , soft drag shocks and the no front bar , big rear bar to make up for the front , makes for a unenjoyable road car
im working more for street /autocross , tight steering and predictable control and good braking , the car was a handfull when i bought it with the worn out bushings in front and rear . new bushings , the bars and 16" wheels really tightened it up .