hmm.. kinda strange typin' english on the dutch side, but hey, what the heck..
I've got 2 cent's laying around about the piston:
I think there's not much bad to say about using stock pistons on a 'spinbank (draaibank) and lowering the compression by 'scrubbin' (afdraaien) down the center comb/circle/hole. As long as you do your maths right, don't go bezerk, and do it your self. Offcourse: new mahle schmiede kolben are the best things money can buy.. but be real: are you going on track? are you fittin it all in a new audi TT? No, you'r putting it in your own dream car (prob. an Mk2 golf), and are looking for a real big ton of fun.
friend o mine is builing a 1.6 liter 8v turbo charged beast (to fit a polo, so don't ask why he didn't go for a big heavy lumped Golf: Fun ain't a straigt line)..
Here's a piston shot:
Left: An AEE piston with deeper 'inner-circle' Right: standard ABU piston.
For the record: AEE and ABU are both same stroke and bore, only the AEE has 'higher/longer' sides, so the piston won't tip over so easily..
To get a bit of 'extra low' compression, he also worked on the head: only a few mm, but still: overall it wil make that little bit of diff.
This grinding will loose some weight, and won't hurt the valve seats.. Yes, them valveseats are really about 1 mm deep inside the head.. (dunno how a 16v will look but it's just a hint..
He'll be using a CNC cut copper gasket: hopefully it'll hold long enough. Possibly longer than double standard gaskets.. Time will tell..
Greetingz. A non 16vT driver :-)