Hey guys, just wanted to share some photos so anyone interested knows what 25mm spacers look like on a sedan with stock wheels. They are the OEM 18x7.5 with 235/45/18 on. Lowered with 350Z H-tech, paired with Koni Yellows. Sorry about the potato quality, only had my phone with me at the time.
The spacers are 25mm hubcentric (wheel centric too) from Precision European Motorwerks. I found them on Amazon at first for ~$62 a pair and they had good reviews. I then check ebay to see if they listed there as well, and sure enough they were, and for only $55. Purchased two pairs, and they arrived at my house in two days!
They installed without issue. Before bolting on, I checked for play between the spacer and the hub and also between the spacer and the wheel. It was dead nuts on. Diameter spec is almost certainly within 0.001". The quality of the machining was excellent (I am a mechanical engineer by day). Metric 10.9 studs were used in the spacer, which is the equivalent of grade 8 bolts. No problems trusting those.
I applied copper anti-seize lube to the back face of the spacers and to the OEM studs since I probably won't be touching them again until I need to replace my rotors again. Tightened to 85 ft-lbs. I used a 2x4 and the power sliding seat to keep pressure on the brake pedal while I tightened the fronts.
The rears came out a little further than I was expecting, so I had to roll the fenders a bit. Used a heat gun and a 2" sch40 PVC pipe, about 2.5' long. Each side took about 20 minutes to roll.
Haven't had much time to drive around on them yet, but everything felt pretty much the same on the drive to work this morning. Didn't notice any bump steer or other effects from increasing the scrub radius. Also did not notice the effective decrease in spring rate from increasing the length of the lever arm. No vibrations whatsoever. Will update with any additional impressions, but for $110 I am very happy so far. Really enjoying the look of the widened stance.