Part of the answer depends on who you are. Do you intend to do some of the maintenance yourself; have some experience and tools? Do you plan to take it to a dealership for most of the work? Pampered and polished with a high-end stereo, or a few paint chips on the nose and worn leather inside?
I agree with what Maytag that mileage is less important than how the car has been cared for. He bought his with about 150k miles on it and has flogged it on the track and done some major repairs himself.
I have a broad spectrum of 986s from 46k miles to over 180k miles. A car that has just under 100k miles, but has not had the suspension refreshed and coolant tank, AOS, and water pump replaced is likely to run up a lot more cost than a 140k mile car that has had all of that done. If you are not VERY familiar with these cars or excited about finding things that need to be fixed AFTER you buy the car, having a reputable Porsche mechanic do a Pre-Purchase Inspection (~$350) is money well spent. Personally I like to buy them cheap and find out whats wrong later, but after buying more than ten, there are still things I miss with my own inspection. An unbiased third party does it best.
IMS: Be wary of claims that the IMS has been replaced if there is no good documentation. Some cars I have seen just had the seal replaced and the owner considered the IMS fixed. Some people have had an IMS bearing start to fail (metal in the oil), then put a new one in and quickly sell the car before the damage to the rest of the engine presents itself. Not all IMS replacements are the same - I'm not going to push an argument about brands and styles here. Search, read and make a choice. My opinion is to have it done when you replace the clutch. It sure would suck to have one fail before the clutch needs to be changed though. Then again, it sucks to have a rod bolt break or cylinder head crack just after you do the IMS. These are 15 to 20 year old sports cars, there is inherent risk.
A water pump replacement at a shop could easily cost $1,000. DIY could be ~$250 for a Pierburg water pump and a couple hours of your time. A window or door latch that doesn't operate correctly could also cost near $1,000 to have fixed at a dealership and under $200 in new parts to fix yourself. We're here to help and Pelican Parts has some great articles:
https://www.pelicanparts.com/boxster/boxster_tech.htm ...a good fresh paint job is probably the most expensive repair one of these car can have other than an engine replacement.
That's enough for one post. Welcome to the forum.
