Originally Posted by downwardspiral
How much would a custom set of Mahle's be though?
Not much. Custom pistons out of places like JE or Wiseco cost an additional $250-$350 as an engineering fee.
Everyone pays the engineering fee. Unless you're an engine market with 10's of thousands of potential customers, forget going cheap.
$250 is nothing compared to the total of $1300 or so it would actually take to make the pistons.
What would really suck is if you didn't pay the extra money and your piston diameters would have to be undersized to accommodate the extra thermal expansion of the forged aluminum. No iron piston coating + cold start slap means a heckuva lot of skirt wear. See how long that piston lasts.