Some asymmetrical stuff is cool. Specially if its for racing and it serves a purpose. And the Manta ray is my favorite asymmetrical custom...
I find myself drawn to cars that I already feel have good proportions. Not cars that need work to attain them. I know it when I see it.
Proportion: The concensus of 51% of the majority of a group that find something dimensionally appealing at any given time. IE: To me Brittany Spears at 17 was proportioned properly. To you J Lo may have the proper proportions. On any given day this ideal of proportion may vary. Disproportioned: That which 51% of the majority may find to not be of the ideal shape. IE: Brittany Spears at 24 or immediately after child #2. Interestingly, even though something may be obviously disproportioned to most, there will always be a few who feel that this is the ideal. And thus you will always have ugly things.
Proportion means you are for portions, or pro-portion. Antiportion means you are against portions, or anti-portion. As it applies to us, if you are proportion, you like parts cars. If you are antiportion, you like complete cars. If you like both parts cars and complete cars, you are bi-portion. So simple.