I sold my Birkin last year and bought an 09 Boxster...The IMS problem extends thru the 2008 Boxsters. The adult woman in my life hated the Birkin...too hot...noisy and snug fitting...my granddaughters thought it was the best thing on wheels. The Boxster has been faultless...they are pretty uncommon in Arkansas since we have not had a Porsche dealer in 25 years, so I get a lot of looks and comments...but not like the Birkin. The cold AC is great with the Arkansas summer.
If you can, get the Boxster inspected by a Porsche shop. They will know what to look for. Parts prices are out of sight.