I don't remember where I read it, but a few individuals with the amsoil by-pass have had bad numbers on their analysis, so I guess it all depends on your vehicle,

Here are some numbers from a guy using the FS-2500.


We have 4 trucks that are using the FS-2500 filtration system, works awesome. You are extending your oil changes to well over 10,000km and we did a bunch of oil analysis when we first installed them and the oil was still pure after 8000 km. I say if you want to save money on oil changes it is a worth while product to pick up. It will pay for itself within 2 years depending on how many km's you put on in a year

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07 2500 4X4 MegaCab 6.7 Edge Juice W/Attitude EGR unplugged Intake Baffle MIA XRT TUNNER 5" TBE 6" AUSSIE STACKS (INSTALLING NOW)