I need to buy a conter weigh and I trying to find out the differences between the SRmotorsports and the OEM counter weight from mazda so I could put on my fidenza flywheel later on. I know the SR say it light weight but for $159 from SR and $89 from oem theres a big price difference. help please

Everyone uses the factory counterweight. That's what you'll get from them but apparently with a markup. It doesn't matter where you get it from. I have an SR flywheel on my RX-7 and I used a stock Mazda counterweight.

the SR includes bolts, the other one may not. Also SR is known for marking up stuff.