I bought mine through a mechanic/dealer, and had them fix the IMS bearing, rear main seals, chain tensioners, and switch to a metal water pump. Those were the main recommended preventative fixes I heard about.
Yes, you are right. Given how cheap they are right now some people get sticker shock when they learn a replacement will cost around $10k. That sometimes is more than half the cost of the whole car.
I've seen most prices for replacement significantly lower than $10k - usually closer to $2-3k (https://www.6speedonline.com/forums/996/241595-ims-bearing-m...). Plus there are a few other things that are easy to do at the same time (like rear main seals).
As long as the IMS bearing hasn't already gone out, it's just(!) a matter of budgeting for replacement when you price the car.
I've been seriously thinking about getting one but haven't found what I want yet.