when a cylinder has low compression, what's the likelihood that i need new pistons? and anyone with experience, how much did it cost you to get your compression back in good range? thanks

 

First you need to find out what is the cause of low compression.
Remove spark plugs and pour a little oil inside of cylinders and measure compression again. If compression increases than you should check pistons-rings part. If compression remains on the same level than you should check valves (cylinders head).

 

okay. so how much am i looking at most if i were to replace the rings per cylinder and a valve job per cylinder? to get it back to oem and running of course.