Yeah I cant find any information about the weight of the stock set up. Didn't think it would be enough to cause a 2MPG difference between trims, is that the only difference in components? I think its more than likely that those who are focused on their Accords performance, will go for aftermarket set ups anyways. Larger tires make sense on a FWD car.
Not necessarily. Larger tires can negatively affect handling precision. These tires are are very large anyway, at least for the size/weight/performance of the car. I have noticed some tramlining with mine. As we know about mass, it wants to remain at rest when at rest and remain in motion when in motion. Increasing the speed of rotating mass (acceleration) requires more power and, by definition, fuel. Decreasing the speed of rotation (braking) requires more braking. This is a flywheel effect. Reducing the unsprung weight allows the wheel to follow the changes in the road surface improving both ride and handling.
Car manufacturers are concerned with durability and cost. This can compromise performance characteristics of the wheel design. Current styling trends seem to demand very large wheels and lower profile tires. A few years ago Car and Driver magazine compared performance characteristics of 15/16/17/18” wheels on a VW. Tires were sized to keep the OD the same. In every case the larger the wheel the slower the acceleration, the longer the braking distances, and the most fuel consumed. No, there is no other apparent difference between the Accord with 17” wheels and one with 19” wheels. The 2 mpg difference applies to both the 1.5 and 2.0 engines. During my car shopping, originally I had decided on an EXL 2.0T because of the difference in the cafe numbers. I assume there is a similar difference in the braking and acceleration. For me, the value factor was better with the Sport model.
I purchased aftermarket wheels for my 2011 GTI and reduced the wheel weight from stock by 10 lbs per wheel...significant! On my 2015 GTI, I did the same with 6 lb reduction per wheel. All wheels for both cars were 18”. Tire weights seem pretty similar. Guys tracking their GTIs are getting good results by reducing the wheel diameter and upsizing the tires to compensate. I am thinking of 18” wheels for my Accord. Tire Rack has lots of dimension data on their web site.