Hello guys!
What size is better for rear axle?
10J ET40
10.5J ET45 ?


Velgen 10.5J +45

When comparing those specs, with regards to clearing the rear fender, they are basically the same.
The 10.5J will be just less than 2mm closer to the fender than the 10J.

I guess some other questions to ask first are: What size tire do you plan on running? How much are you lowering the car?

Edit: Just found the vehicle is on J5's with 235-35-19 & 265-30-19.

lowering 3IS on RC F springs and shocks which shipping from Japan. Its all about 2cm drop.

I guess in theory they should fit, but wasn't sure how the spring rates and dampening would work out.
The RCF has a heavy V8 up front, so I would think the spring rate would be a lot higher than an IS...which might make the IS front end actually higher than stock, instead of lower.
If you think about in in reverse, what if you dropped a V8 into an IS with the stock springs...would likely make the front of the vehicle sag.
I could also be completely wrong lol!!

Definitely post some pics once installed...I'm curious to see how it turns out.

Sure man!
My bro just installed RC F suspension on 3IS. all got on bolt on. But he did a swap - 5-liter engine.