My rear tire is almost at the end of its life, so I was thinking of changing from 16" rear rim to 18" with a 130/70/18 tire.
I've photoshopped an 18 incher for comparison. What do you guys think is better (aesthetically).

 

18 makes front tyre look too big IMO

 

18 ftw

 

I vote for the 18"...

 

18 will be cool, I think it would be perfect if you did the 18 and a 21 up front!

 

You need a 3rd option. 17"
I got me a like new Deuce wheel, 17 by 4.5 on my '06c

 

I'd do the 18.

 

I personally like the look of the heavier wheel being in the rear, but my main reason for commenting is to compliment your Photoshop skills. Impressive. Especially the background through the spokes and shadows on the 18".

 

18" that would look sweet.

 

Might look good but handling will suffer and it will be more of a slug off the line.

+2 kudos on the PS skills tho.