Problem with modded B5 TDI

Maybe someone can give some thoughts over this.

Today drove 250km and at the end when I was accelerating hard I lost one of my mufflers.(broke off from rusty welds) Because of muffler crackling noise I did not hear anything else abnormal. I pulled aside and took that hanging muffler off.
Started driving again. But now there was problems. Intake makes a bit of subaru boxer sound (i have cone filter, everything is loud and clear). Turbo spool at lower rpm's is erratic. I can feel it trough shaking car and I can see it on EMP gauge which is jumping up and down. And there is rattling sound coming from top of the engine.
If I drive it beyond 2300-2500rpms (achieves max boost too) then it sounds and feels good, same as before.

What happened to my engine?

Specs:
AVG TDI
GTB2056@2,2bar
0,216 nozzles.
135hp at wheels

I'll bite...any codes?

Holed lifter due to a bad cam?

Heh. should have looked a the sig a little closer. VE engine? I would check compression, then perhaps check the pop-pressure and spray pattern on the injectors.

Is there any additional smoke coming out the back?

Do you have access to VCDS to check injector balance?

Checked compression's. Everything ok there, 490-500psi.
No codes and injector balance is pretty much the same it was before (differs form -0,5 to +0,5) Nozzles are changed and pressures set about 15k km ago.
No additional smoking.
Since did not find anything that moment I went driving. Have driven now about 20km and clattering is really loud and car is stuttering heavily.
Will pull valve cover and hope to find dead lifters and maybe even cam. Oh boy that would be simple solution.
I tried to listen with tube and it is definitely coming form first or second (or both) cyl.
And seems to be coming from top of the engine still.

New cam and lifters for me.

Ummm.... I don't think that hole should be there

Double check the stem on the valve with the borked lifter. You don't want to keep it in service if the stem is munched - it could damage the new lifter, or worse - fracture and drop the valve into the cylinder.

Windex, do you mean valve tip? Where lifter contacts valve? That seemed ok.

..so took it apart. Other lifters are ok. No dishing or something, completely flat and firm. Cam is a bit worn but nothing bad i think.

So what destroyed first cyl exhaust lifter?

And how to proceed. Hopefully tomorrow my new camshaft arrives and I can start to put things together.
I thought that I will drain oil, change filter and put new cheap oil in for flushing. Let it run a bit and drain again, new filter and new oil. And hope for best? I reckon that there a bit of metal shavings everywhere.
Am I on the right track?

E: just in case i will add link to picture. Maybe someone can tell something from it. Lifters are a bit red on top. And a bit scratched. Not very best looking.
https://scontent-arn2-1.xx.fbcdn.ne...=b54bda8285efe7cd7faf791716e27b48&oe=56572858

The part in red - it can get mangled if the inner part of the lifter turns sideways as your did.

Given the wear on the other lifters, I would want to know the maintenance regimen on the engine - what oil was used, and the interval it was changed.

I have not owned this car for very long and exact history is unknown.
Engine has 430k km on it. I have driven last 30k and changed oil twice. (15k interval). I have used Castrol turbo diesel oil, fully synthetic.

Lot of km's. This might be normal wear.

Put all together yesterday.
Elring valve stem seals, INA lifters and Febi cam.

Sounds a lot nicer than ever before.
Old cam was worn about 0,4mm from tips and if you looked at old and new cams then you could see that lobe sides where worn straighter. New has nice curve there. How to say.. opening ramp?

All strange sounds are gone. Subaru sound and spool-up air gasping sound (this last one has been there for some time, if I only knew .
Nice and smooth now.

Thanks to everyone.