Why does the GTS get 1 less mpg?

[hotdog]

i. the engine specs are the same as the other MTs,
ii. all have the same final gear ratio
iii. all have the same curb weight

some reasons i can think of is the weight is listed incorrectly as 3241 ( maybe the body kit + lightweight 18s + tires add weight over the S?)

Any thoughts? Suzuki doesn't mention individual gear ratios- that's another thing i was wondering, if the GTS has unique gearing

[KuroNekko]

Larger wheels. Bigger the wheel, the less efficient it is for fuel consumption. The benefit to larger wheels is enhanced handling. Also looks better. GTS and SLS should have similar fuel figures given the same drivetrain.

[hotdog]

Believe you are right- Thanks!