With regard to the 2000 Boxster, some had a double-row IMS and others had a single-row. I've been told that the only way to determine the type of IMS is in a 2000 Boxster is to remove the transmission and look at it.
I have a 2000 Boxster. When I had the clutch replaced, the technician told me that my car had a double-row IMS. My car was built in Finland in September 1999. My hypothesis is that the cars built in the early part of the 2000 model-year production run are more likely to have a double-row IMS. However, I have not seen a reliable source that supports my hypothesis.
I think this website contains accurate information regarding the model years with each type of IMS:
https://lnengineering.com/products/the-definitive-guide-and-faq-for-porsche-ims-bearings/porsche-ims-bearing-problem-years.html
Specifically:
1997 Porsche Boxster 986 - Dual Row IMS Bearing
1998 Porsche Boxster 986 - Dual Row IMS Bearing
1999 Porsche Boxster 986 - Dual Row IMS Bearing
2000 Porsche Boxster 986 - Dual Row or Single Row IMS Bearing
2001 Porsche Boxster 986 - Dual Row or Single Row IMS Bearing
2002 Porsche Boxster 986 - Single Row IMS Bearing
2003 Porsche Boxster 986 - Single Row IMS Bearing
2004 Porsche Boxster 986 - Single Row IMS Bearing
2005 Porsche Boxster 987 - Single Row IMS Bearing (some late 2005 builds may have the larger, non-serviceable IMS bearing)
2006 Porsche Boxster 987 - Larger, Non-Serviceable Single Row IMS Bearing
2007 Porsche Boxster 987 - Larger, Non-Serviceable Single Row IMS Bearing
2008 Porsche Boxster 987 - Larger, Non-Serviceable Single Row IMS Bearing
If you search this forum, you will find many opinions. The member that I suggest that you give the most credence to is JFP in PA. He has hands-on experience with the cars and (in my opinion) knows what he is talking about. There may also be some posts from Jake Raby that provide good advice, but I don't think he has used this forum for several years.
Good luck with your search.