IMS bearing questions
 

I have a 2001 and 2002 Boxster s. Replacing the clutch on one and think I want to perform ims upgrade on both for piece of mind? Does it matter which bearing I buy? Single row or double row...are there different fits for different years? My 2000 had a double row, but I hear that this changed at some point in 2001. Anyway to tell before the car is apart in the shop?

No... You will not be sure which bearing you have until it's apart. You can estimate it based on VIN but don't bet the farm on it.

does this mean that I need a different kit based on whether I have the single or double row for retrofit? when I buy the parts, want to make sure I get the right kits in advance.

if you don't know and are using a professional installer, go to someone familiar with the IMS replacements and order the parts after the transmissions are out and you have confirmed which bearing you need.

This is a pretty common practice for folks in those questionable years where you dont know for sure which one you need.

OK, I have figured this out and appreciate the comments. flange sizes are different depending on which bearing you have originally.
If I have double on 2001, need a different kit for the 2001. Seems most if not all 2002 are single row. Anybody seen something different?

single row has original cover dish depth = 19.27 mm
double row has original cover dish depth = 13.34 mm

Hope this helps others with the same question.

and here is a nice link with great info:
https://www.pca.org/news/2018-01-05/pca-spotlight-extending-life-your-original-ims-bearing-0

Find someone who has done plenty of IMSB replacements. If you search this forum you'll find a story from someone who had his IMSB replaced by a Porsche dealer who tried to take shortcuts and wrecked his engine. Luckily for him they made it right and rebuilt or replaced his engine.

Absolutely no way to tell short of looking at the flange after the engine and trans have been separated. Variations have been observed by mechanics doing hundreds not to mention replacement engines could have neither single or double row.