bro westcoast,
since u aledi pasang, no point turning back lar, just use it hehe.... the sound is like cicak coming out from ur speaker and that is if you play SQ (sound quality) and not SPL (sound pressure level), means if ur the one that likes to blast ur music outloud at ear banging level, then no worry the cicakman won't be there, but if ur the one that listens to Chai Qin, Au Sui Keong (correct aar?), Norah Jones, or Eric Clapton or others, and only speakers like Focal, DLS, Morel, DynaAudio, amps like TRU, Steg, Genesis, with probably Monster Cable or some expensive van de hul home audio brands, then u can actually hear it.... (please be informed that i'm not so crazy until all the things i mentioned above for SQ, OK OK maybe just half of it)
actually can tell from various standalone ECU manufacturers eg. motec has claimed that EMI can indeed intefere with the electronic devices, however they also claimed that they do have powerful shielding from any radiated interference.... dunno whether mitsubishi or proton ever design any ECU casing to shield EMI? that i don't think so due to its stock carbon type plug cable....
it's not always bout retuning ur SAFC, it's about precision of signals received, ur putra is running on Karman MAF, and it operates on Frequency (calculated in hertz) and not voltage like most MAP sensors, so wat u think EMI will do to the Frequency? however, ican't prove this to you coz i dun have any EMI / Radiation Detector, maybe can pinjam and trace how big is the EMI produced by ur NGK blue cable at different revving range?? then post it here and compare with the stock ones??? then from there we can trace how big an impact of X value of EMI at what frequency can hurt any operating electronic devices......... hehe if u can get the value then contribute something to this thread lar....
