Looking at their website they list 2 diffs,

*G50: 911 1987-88, 930 5spd 1989>, 964, *********993, 968
*996: GT2, GT3, turbo 6MT rear

40.309.160WK
$1,395.00

And

*996: 1998-2005 6MT (excl C4, GT, turbo)
*986: Boxster S 3.2L 6MT

40.309.165WK
$1,395.00

So which one would be better? The vehicle has no traction control and small tires.

 

According to the above list:
If your car is GT2, GT3, Turbo, 6 speed the .160
If 1998 - 2005 C2 the .165

 

I've been seeing that too, but I've been told that both diffs are the same "dimensionally" so I was assuming they have different lock up or ramp rates.

So are the two diffs not interchangeable?

 

Just call Wavetrack - they are in Sol Cal and they pick up the phone. I love mine in the 993.
Even if they are dimensionally the same, they might have slight differences.
I got the 2nd Wavetrack built for the 993 after my buddy found out the bad way that the 964 g50 version didn't work on the 993 G50. Wavetrack completely rebuilt my friend's 993 G50 Trans for him gratis..... 993 G50 Wavetrack's now have the "Stonehouse" groove around the diameter.

 

Sounds good. I'll call them and post up what they say.

 

Well called them and was told that both diffs are internally identical, so there must be something different with the actual diff housings. They couldn't give me anymore information as to what the actual differences are between the 2.

 

Call Matt at Gaurd, get good advice and great a product. Is it 1395.00? No, but it works and he stands behind his products.

Cheers

 

the two Wavetracs are almost identical - and obviously will perform identical but the main difference is axle retention

160wk sun gears are designed for bolt in retained drive flange
165wk sun gears are designed for snap ring retained drive flange

 

So which one is the correct or preffered model for a 996?

 

Non- Turbo & GT3 drive flanges are retained with snap rings

 

A strange question, no? As indicated on Wavetrac's website, if you have a 996 "GT2, GT3, [or] turbo 6MT" you go for the first diff. If you have a "996: 1998-2005 6MT (excl C4, GT, turbo)" you go for the second.

EXCEPT that sometimes cars in one of these groups were manufactured with stubb axles normally fitted to the second. Like mine. So I bought the second, and then had to switch to the first :-(

In short, if you can check to make sure you have the type of stubb axles normally fitted to your type of car, do so, then order the diff. (I suppose the flanges referred to ab ove are what I refer to as stubb axles.) If not, order the diff for your kind of car, and I suppose 90-95% of the time you won't have to exchange it.