(I'm not dvkk but..) Those type 4 blocks \"usually\" don't need this machining , but even if it does it's probably not more than $100. It's all the rest of the stuff that will kill ya. Reconditioned rods , new cam and lifters(they wont regrind hydraulic lifters) , bearings , gaskets , etc. etc. which you will certainly also want to do once you have it all apart.
But I would say that by far the biggest killer of these motors are the heads. Either a broken exhaust valve or dropped seats. Either of these can be sudden death with no warning at all. I'd personally worry more about this than low oil pressure. Type 4 heads are notorious for this. I'd recommend a complete rebuild (if their not cracked)with all new valves AND SEATS installed by someone who understands these heads.(not sure who that would be) Other wise , it's all a bit of Russian roulette
btw, I've heard that new replacement heads are even worse.
On the bright side , I think if all this was done you will have a super solid , better than new motor that you will never have to worry about.