Something tells me your garage did not do a thorough job. Somehow the IMS has to be junk and they just missed it. I would recommend to keep searching for a garage that tells you it is the IMS. Until then, you still have a problem. Probably a big chuck of cylinder floating around some place too.
My bud had a noise in his 996 motor and assumed the worse. I told him it was likely something stupid. It turned out to be something to do with the muffler. I think we have all been brainwashed. Heck, I did the IMS replacement too on my 50k car. I will probably do a 100k as well.
People keep looking, hoping for these cars to fail. Not sure why. Maybe it's the change to water cooled. Maybe it's the fact that these cheap cars can out perfrom a lot of the older more expensive cars. Honestly, mine has been chugging along nicely for close to 3 years now. I change the oil and do all the preventative stuff. Otherwise, no issues what so ever. Also, the ones that I saw in my town years ago are still there. Seems they are chugging along too. (small sample size I know).
As far as responses to the Boxster/996, most people just know it as a Porsche, not a Boxster, 911 or Cayenne for that matter. Only ones who seem to care are us. I still get kids waiving to my lowly Boxster like I did with my 911. Only difference now is I have more money in my pocket and A/C that really works. Call me crazy but I think the 986 is one of the most interesting cars visually Porsche ever built. Crazy stuff.