[bobthecabbage]

I have no experience with replacing flywheels but a solid flywheel is going to give you an engine like a tractor or old van according to the internet.

That and adding a bigger turbo is probably going to result in a short engine life!

I would suggest that for more power you should regularly service your engine, maybe use a 5W30 oil, clean your EGR or replace it, clean the MAF or replace it with an OEM part (or genuine). Service your brakes so they don't drag. Check your vacuum and boost control solenoid.

I don't know whether putting a bigger turbo on it and risking headgasket failure is worth the hassle (or even practical).

Maybe have a look around for a T4 instead?