And if doing all that, it's equally worth getting a TFSI crank and making it a stroker build... slippery slope, weeee!
Probably not for stage 1 lol...
Anyhoo... back at the OP...
In my experience 1.8t pistons don't 'wear'... I have yet to see any on all the engines I have worked on that are unserviceable from 'wear'... pitted from pre-ignition, dented from valves, broken/worn rings, worn gudgeon pins but not worn pistons or skirts as such...
If you have obvious wear then you have bigger issues as the bores are most likely damaged...
You have not mentioned that you have measured the bores for wear or ovality or why you are rebuilding the engine in the first place... engine rebuilds don't normally happen because you feel like it... its usually prompted by another event such as low compression etc... just basing piston replacement on what a piston looks like without taking in other factors such as bore wear seems a little bizarre to me.
'New' OE type pistons are going to be around 100 quid each... its pretty pointless dropping std size pistons into worn bores without checking for bore wear at this point else you could end up spanking 500 quid and still not getting a sound bottom end..
At the very least you need to inspect the bores, measure wear and ovality and if its all in spec then you can get away with new rings and a bore hone...
Do you have some decent pictures of the pistons showing the wear? its normal for the black PTFE coating to 'wear out'...
Please also note that not all 20mm pinned OE pistons are the same... I had worn pins on my AMK pistons so used the pistons from an Ibiza Cupra as I couldn't get hold of separate pins to replace them and the K03 turbo'd 20mm pins are different to the K04 turbo'd ones...
<tuffty/>