I own a 2015 is250 awd f sport , I'm going to be buying 19x8.5 F and 19x9.5 R wheels , my question is what is the lowest offset I can go with and tire sizes with no fender mods or camber , the car will be dropped on rsr down springs , thanks in advance

 

+30ish for the front
+40ish for the rear

 

+30 Front
+40 Rear
Would be good.

 

How about if the rears are 10"?

 

I'd go between 45-50ish

 

Look at my build.
19x8.5 +35 (You can go 30) FRONT
19x9.5 +40 REAR (Perfect)

Looks great

 

with you being AWD, the closest tire sizes for you are as follows:

CLOSEST (.1% difference) Rear: 275/30/19 - Front: 235/35/19
NEXT CLOSEST (.4% difference) Rear: 265/30/19 - Front: 225/35/19

depending on how aggresive you go will depend on if you can fit the 275/235 config.

 

Thanks fellas for the replies