Wheel offset - conflicting information

[jabrax]

Need to order new wheels, but I'm confused about the preferred offset size based on the original wheels, versus what some stores and sites say i need.

My situation - the car currently has 18 x 8.5 (offset unknown, car passed on to me from father) all the way around. - I think it is just a touch wide in the front for my taste. Also, is seems that the car doesn't roll freely when off the gas (could be in my head and have nothing to do with the wheels ).. So going to try 18X 8. Seriously thought about 17X8 but scared i would be disappointed after having a taller wheel

Issue
Original wheels 16X7.5 with 45 offset all around. (info from researching this site and others)

When i configure the vehicle in some sites it shows high offsets +38 up to 45.

Others say they only guarantee or recommend fit for 20 - 35 (they classify as medium)

I played with the calculations from other posting on this site. The guarantee statement has me spooked

[jabrax]

Think i figured it out.. Please yell if i am barking up the wrong tree. Found a video that describes how to find the offset of a wheel (if someone ever needs this info, let me know). This was important for me as i know what the current wheels look like on the car (94 NA). Perfect flush on the back, but just a tad wide for my taste on the the front 18 X8.5 25mm (by my calc).

According to the fitment guide, when compared to stock I am (+) 1.28 outside and (-) .28 inside.... Tire is inch wider and shifted to the outside

Stock – 16 X 7.5 45offset

190.5
95.25
50.25 --- 140.25
------------------------------------
18 X8.5 25mm

215.9
107.95
82.95 --- 132.95

Out +1.28 ins - .28

Whew a full days work to figure that out and realize i have to start wheel search all over as the ones i almost pulled the trigger on wouldn't be wide enough. Soooo gonna stay with 8.5 with a 30 or 35 offset.. i think

Enough talking to myself for one day, i actually learned something today, unless someone yells back the f up, you are waaaaay off