well I just recently installed an alpine deck in my alero and I had the option of running the cheap wire harness for 15 bucks or the good one for 95 bucks. Im cheap so I bought the $15 one and I lost my door chimes,abs light(never seen come on before),and my airbags(hopefully I dont hit anything too hard head-on). But it didnt seem to affect anything so far.
On the speakers side....Ive got all stock speakers that I use with my two 12'' subs and I always have em cranked, yet controlled. And they're fine. As long as you know what you're doing you'll be okay. But maybe in the future sometime you might want to save up for some decent speakers just in case
