[seningen]

It’s all about budget.

Due to outsourcing of block casting, 99’s have seen a higher percentage of cylinder liner cracks, d-chunk failures and cracked cylinder heads.

All things being equal, I’d skip a 99.

I’d seriously consider an S if it fits your budget.

I daily drove a boxster S for 4 years. Tracked another S for several years.

Maintenance doesn’t have to be that high.
IMS as you mentioned, although depending on the cost of car, might not be worth addressing as failure rate vs cost doesn’t warrant the investment.

Typical faults... (I’m sure there are others)
(All diy depending on skills)
Head light switches
Faulty inhibition switches
Window regulator failures
Plastic switch failures in door/window circuits
Plastic Rear windows cracking
Clogged rain water drains
Burn barks on headlights
Idle pulley failures (I think this is from some serpentine belts are ever so much smaller than stock, that they fit, but torque the pulley)
Sticky starter motors
AOS failures
Waterpumps are weak and can fail
Expansion tank resovoir cracks/leaks.
Variocam solenoid failure
Variocam chain tensionure guides wearing

Slipping IMS gear on press got tube
IMS Chain tensioner wear
These last two are really not fixable without engine tear down.