VAC Motorsports Billet Differential Cover, BMW E82/E87/E90/E92/E93 Non-M

Pros:
-Cools the LSD gear fluid much better than stock
-Adds port to monitor differential temperature
-Adds drain/fill plug for easy fluid change
-Shiny

Cons:
-$800
-Can be low to the ground (no issues, surprisingly even in horrible Philly roads)

~~~Why bother with this?~~~
This is one of those items that seem like a true enthusiast product for the "hardcore track junkie."
I thought the same until I discovered that I might be in serious need of such a product.

Many of you have LSD's in your OEM diff unit with BMW's "lifetime" gear oil.
Unfortunately, I recently discovered that this gear oil doesn't last anywhere near the "lifetime" of the vehicle, especially when coupled with a Quaife LSD and a few (15+ ) very hot track days.

My old unit had begun to spurt gear oil after track events.
After track events I would go under my car and find the pumpkin to be covered with gear oil. I would then clean it off and begin to worry. At first I thought it was the seals so we replaced those. Then after replacing the seals, the diff was still getting fluids all over itself after track events.

After some researching, I suspected it was because the diff oil was boiling and coming out of the top vent. After opening my diff up and seeing that the gear oil had gone to an extremely nasty shade of black, it was confirmed that I had cooked my gear oil and cooked it pretty bad.

~~~Which begs the question~~~
If I, an intermediate level driver at best, is cooking diff fluid in the New Jersey weather, how the hell is your diff fluid holding up if you live in a warmer climate, producing more power (all tuned n54...), or have more experience tracking?????

~~~Driving Impressions:~~~
This was the most surprising part. My Quaife unit felt like it was slightly more progressive, almost smoother with the new fluid and not boiling the fluid at the track. I hadn't expected a change at all but it was noticeable today at the track in 100+ degree weather when compared to just two weeks ago. This could also be attributed to the fact that my previous fluid had been boiled multiple times and was probably in horrible condition. Nevertheless, it's looking like this new differential cover will prevent that from occurring again.

On the street I've had zero clearance issues. I don't baby this car around the mean streets of Philly and South Jersey. Our potholes and bumps are legendary. I've seen a Ford F150 get stuck in a huge pothole in West Philly before. So far my lowered 335i has confirmed the VAC note that the race length (long finned) differential on a lowered vehicle generally has no clearance issues. Obviously if you ran through a curb that would take off your front bumper and various other underbody parts, you would probably scratch this differential cover. Best part is that even if you do hit it, it's made out of one piece forged billet aluminum so it's strong as hell.

Review link with photos: http://www.e90post.com/forums/showthread.php?t=720740