Bad compression, two cylinders...need opinions/help

[barnum]

Hey guys, been awhile since I've been on here.

My 02 R50 has been running rough at idle for a while now with P0300 coming up frequently (multi-cylinder misfire) as well as excessive oil consumption since I got it 3 years ago. Other than that the thing runs great. Finally really started digging into it to understand the issue and have come down to PCU failure of some sort based on the following diagnosis:
- Air/fuel filter swap -> no diff
- Plug swap (OEM NGK's) -> no diff
- Power balance test -> found cyl #1 made no difference in idle rpm
- Coil test -> OK
- Check spark -> OK
- Vacuum leak check -> OK
- Dry compression test -> cyl #1/4 low (~50% of highest)
- Leakdown test -> cyl #1/4 had leaked into exhaust stream, negligible leak in crankcase (piston may have shifted as I did not lock engine position)
- Wet compression test -> cyl #1 jumped 22psi/cyl #4 jumped 70psi -> most likely bad rings/pistons/or cylinders

So, I'm at the crossroads of sell, engine swap, or repair. I want to know if this worn rings, compression loss is a known issue with VQ35DE's or if this is an outlier. Reason being, if I can get an engine swap done for $1500 that might be the way to go but I would be taking a gamble with a junkyard engine and don't want to get another if this issue may come back because of its prevalence. Anyone know a little better than me the known issues with these engines at high mileage?

I'll have to perform the leak down again with the engine position locked to confirm or deny leak into exhaust stream.

Info on VQ35DE longevity appreciated. Thanks.

[atraudes]

I don't know that it's a hugely prevalent issue on our engines any more than other cars out there. Do you know if it's sucked in any power valve screws or butterflies? That's the thing I've heard many times here that causes low compression and the like. Regardless, that would be the absolute one thing I'd look for on any donor engine you're entertaining. If it's missing screws, walk away.

On a somewhat related note, the P0300 is probably caused by a coil pack or two going bad. I had that happen to me and the misfire would only happen sporadically, then more and more frequently. That's neither here nor there at this point, I suppose.

Good luck!