[Perfectlap]

I paid $1k for the water pump. My indy charges $85 an hour.

$3K for your IMS quote includes the new clutch which you already have so you can discount that.

An experienced Porsche shop can do the IMS in a day, maybe you'll need a new OEM flywheel $600 (I think) if it wasn't replaced, you can opt for a less expensive IMS bearing (Pelican) so I'm guessing $1,500 all in. The point is to replace the original bearing which is the one that nearly always fails. An IMS failure on a second bearing (Pelican or LNE) seems very rare if a proper inspection was done beforehand to determine if the original bearing had already compromised the engine.
While you're at it service the axle boots and replace the RMS seal.
Although some guys have done the their own IMS bearing swaps with no special tools or experience taking down transmissions, it's not a good choice for a DIY job.
The cost savings does not provide a good risk reward proposition.