questions and a few other things

Random please read
Thanks
My vt has a few things going on with it first i cant keep the back bumper clean from soot or the black stuff from burning to rich. My idle is very rough now that i took muffler off basicly did what turbo socks did and custom intake... i have never been in a car that surged as much as this one does its terrible. also forget about a burnout which i love to do wheel hop is the harshest i have felt. my vt is mt.. i have plastic dip front bumper and hood also the wheels and left the chrome part exposed. took off emblems and currently debating on installing the hids with out removing the bumper i will be installing mbc soon i have used b4 installed greddy boost gauge installed rockford p3 12 and alpine amp oh .... my cruise was cutting of randomly on interstate last night just like you were pressing brake drove about 300 miles no check engine lights still doing it... im getting 34 mpg on long trips not using the gauge in car, real mpg..... oh the ride of the vt is seriously rough my 88 crx with 17s and rubber bands with cut springs rides better... whats up with that im worried something is gona break when i hit small bumps or cross bridges on highway. planning on doing the entire car in plastic dip... my dash rattles my doors rattle the car runs like total ass until heated up totaly and driven about 10 miles surgeing jerking hard shifts vibration from the wheels until warmed up also i really dont understand that one.. thanks for reading with all that being said i still love the car... my choices were mazda 3 gti or 370z i could not get over how the vt looks less performace by a long shot than those cars but the looks are the best on the market i wish we could start tuning these things we need a tuner i also have a nissan juke 2011 and had to wait for a tuner for it for about 15 months so hope its not that long i will post pics soon