Zymol75 wrote: ↑Wed Jun 02, 2021 10:21 pm
Well unfortunately that isnt true.
You are correct: the axle widths are identical, as are the majority of parts used.
Nissan still publishes Owners Manuals for those vehicles through their TechInfo sites, and the offset is spec'd in the OM:
99 QX4:
https://www.infiniti-techinfo.com/refgh ... ti-qx4.pdf. Page 10-24 (pg. 283) shows a 16x7 w/ 20mm offset
99 R50:
https://www.nissan-techinfo.com/refgh0v ... finder.pdf. Page 10-10 (pg. 253) shows the configurations for both 4x2 and 4x4, where you'll notice a "Wide" designation...this means they had fender flares. There's a 16x7 on the XE (non-wide/non-flared) trucks that had a 50mm offset.
So, mdmellott isn't wrong in saying that they were both 20mm offset, but that's only true for fender-flared models.
Of course, since you have both the 5-spoke and 3-spoke wheels, you can determine the offsets and backspacing. Just need to measure the actual rim width, divide by 2, and find the difference between it and the depth of the mounting surface. If the tires are still mounted, just need some sort of straight edge to rest on the rim to measure backspacing from.
I can't help much with the lowering springs, aside from suggesting to look into importing lowering springs for an Elgrand E50. Practically identical front suspension as the R50. Rear suspension setup is different, though, but I'd imagine there's a suitable spring out there.