I have a M30B35 from a 91 535i that i want to rebuild. I want to have the cylinders bored out to make nice new ROUND holes and i was kind of shocked at the price for a set of 6 pistons for a B35.

is there some sort of cross reference where I could save some money getting pistons from a different engine or does anyone know of a manufacturer that i could source a less expensive option?

The engine is going to be normally aspirated with the Motronic 1.3 and i'd like to keep the compression at a sane level.

thanks