Bandido, usually companies like NGK manufacture stock or OEM wires.

jevy, sounds like sales talk to me. try mo nalang kung ok yung performance kapag kinabit mo. kung ok then sulit nabili mo. if not then na-sales talk ka siguro nya.

main difference is the diameter of the inner conductive core and sometimes iba rin yung material na ginagamit nila (copper because this is a good conductor of electricity).