Do they work though?

if applied properly yes. they knocked off .01cd from the evo 8...

If only I had a wind tunnel...

The Scanguage will be purchased Wednesday when I get paid,
so I could see how much aero mods help!

yea... you could try tuft testing

Rear Tray, not sealed, but hopefully it helps, the exhaust and right side are not covered:
https://www.fuelly.com/attachments/fo...0897dab52f.jpg
https://www.fuelly.com/attachments/fo...59226d5249.jpg

Lower Grille block:
https://www.fuelly.com/attachments/fo...52c57bf73f.jpg

Rubber seal for top of lights and grill:
https://www.fuelly.com/attachments/fo...74a4fce3c0.jpg

Can you spot the Grill block?
https://farm4.static.flickr.com/3273/...3bcb891727.jpg

Though it is basically invisible in that pic, the lower grill is completely blocked, and the upper grill is partially blocked.

The radiator on the xB is only behind part of the xB's grille, from about the left edge of the license plate to the inner edge of the right headlight (as you're looking at the car). You can just make it out in this shot with the lower grill removed.

https://farm4.static.flickr.com/3178/...3a83578b40.jpg

Since there is almost half the grille that has no radiator behind it, I decided to block air from coming in that part. The upper grill has a block on the left side covering from the edge up to the license plate, and another short one ~3" on the right side. You can just barely make out the edge of the left block in this shot:

https://farm4.static.flickr.com/3060/...4e8bd84286.jpg

For the lower grill I made a block on the left side basically identical to the upper grill, then made a second block that covered the rest of the grill. This way the whole lower grill is blocked for the winter, and come warm weather I can just cut the zip-ties on the right section and open it back up without having to redo the lower grille.

https://farm4.static.flickr.com/3269/...70a89c9c99.jpg
(the "flap" wedges between the grill & the radiator to maybe help direct air into the radiator)

Next up is a front belly pan, but that is on hold until either it gets much warmer, or the $205 beater I bought for a friend is done being overhauled in the garage.

Any MPG measurments with all that work?

Did you air dam any of the wheels too?

I've been keeping up with my gaslog and noting in it when improvements are added. They haven't shown as much as I'd hoped because they are relatively subtle and I'm not good at consistently driving with MPG in mind. I'm too easily distracted. :)

Not yet. I'm goign to try and figure out something for the front wheels at least when I do the front belly pan.

Front belly pan installed.

Before:

https://farm4.static.flickr.com/3050/...6c831110f7.jpg
https://farm4.static.flickr.com/3287/...f223653589.jpg

After:

https://farm4.static.flickr.com/3119/...da7ea3b7f8.jpg
https://farm4.static.flickr.com/3091/...ff4ffd3238.jpg
https://farm4.static.flickr.com/3074/...9fbc3fe551.jpg

Fenderwell detail:
https://farm4.static.flickr.com/3127/...904909af43.jpg

Cutouts for engine/trans:
https://farm4.static.flickr.com/3225/...9ee46c1b00.jpg

I didn't go as far back as I'd have hoped because a)I was afraid of the engine/trans heat melting the chloroplast and b)I wanted to retain access for oil changes/etc w/o having to remove the whole thing. Like my other mods, I made sure not to drill/screw into any metal so I don't have to worry about future rust.

Of all my aero mods, this one has had the most effect. While my MPGs haven't actually gone up, they have managed to stay consistent despite the rapid drop in temps. Also I appear to be able to coast a *lot* further in neutral, enough that neutral coasting down hills/exit ramps is actually worth it now (I used to coast in gear as that shuts the engine off for infinite MPGs)

Would a tiny lip like that really make aerodynamics worse?