What head gasket set to use on an M20 stroker?

[rs4pro3]

E-piston

I-piston

[Bimmerfanatik]

Well I'll be damned. I took a quick peek/feel - I'm almost positive they're the euro 11:1 pistons :)

How about a profile pic of the standard eta pistons? Domed, concave, etc? Also, are the euros domed or concave? Can't tell in the pic - optical illusion like.

[rs4pro3]

11:1-domed
standard eta-dished(concave)

[Bimmerfanatik]

11:1-domed
standard eta-dished(concave)

hm. Now I gotta take a better look...