I worked on the top hats for the 6112s I have waiting to install. 6112s don't come with top hats or isolators (they re-use OEM), but I figured I'd assemble them with new parts while I was at it. It should cut down on install time and then I'll have complete Pro-4X coilovers to stash or sell.
I bought 1/2" (1" lift) spacers from Nisstec, which require longer studs to run. Nisstec offers new top hats with longer studs pressed in, but it's like a $90 upcharge (twice the cost of the spacers). Initially I'd planned to source some longer bolts and weld them into the top hats, but Nissan4Life on Club Frontier found a set of Kawasaki wheel studs that are just the right size
. I don't own a press (I want one more now) so a hammer, vise, and some profanity got the new ones in. They are almost exactly 1/2" longer than OEM, and the spacers adequately cover the excess spline length. The OEM studs were very easy to get out.
Onto the isolators. I cheaped out and bought a set from 'Febest' on Amazon since the price was decent and they didn't come with a bunch of extra bits I won't need with the 6112 install kit. This was kind of a mixed bag as the overall construction is fine, but the design is flawed. The relief cutouts on the top side of the isolator are meant to fit around the heads of the top hat studs. They are cut quite large, and only one of them lined up properly (isolators can't be rotated as they have a 'key' that fits in the top hat). I ended up needing to notch them about 3mm in two places, but they now seat into the top hat around the studs just fine. This issue was present with both the OEM studs and the new ones I installed.
The 6112s have six height settings, but don't offer a great deal of lift at 1.6" max. I've got the circlip set about in the middle at 1" of lift and will rely on the Nisstec spacer to keep me at 2" over stock. I'm really not looking for anything higher at the moment. Just waiting on my spring compressor to arrive. I'm sick of borrowing/renting them and I need to do the suspension on my wife's Subie soon so I might as well get a set of suicide sticks.
tl;dr - put longer studs in OEM top hats for 1/2" spacer, had to notch aftermarket isolators to work with OEM top hat, anxiously waiting for my spring compressor so I can get the coilovers assembled.