if i may share some experience modding my previous e46 330ci full exhaust system..i had to mod my exhaust twice..after some lessons learned and extensive research, i found out that normally people would go for 3 types of quad-exhaust setup (for e46 with spare tyre compartment):
1) extend a pipe (almost 90 degree) just before the exhaust tip (a bit similar to bro moots picture in post #3, but not as smoothly angled as his)
2) extend a pipe from the backbox/muffler (as per pic by bro fahmi in post #6), mostly sold/made by remus, eisenman, taiwans etc.
3) extend a pipe all the way from the mid-section to the tip (as per attached picture)
4) oh almost forgot this one..quite popular too..put fake tips at the other side..hehe cheap n fast...but kantui in the morning/rainy days only one side keluar asap
I did Option 1 at Redzone after converting into CSL rear bumper..car was sent by Red Zone to Wai Heng at the corner lot shop...terrible terrible effect..immediately can feel loss in power...loss low end torque...car pick-up was horrible...sound only but struggling to fly...mind u this is coming from a manual 3.0 liter...believe the power loss is due to the blockage at the end due to the almost 90 degree pipe causing too much backpressure..only good thing (or bad) is the sound is louder..oh btw, workmanship for bumper also very poor..bumper came off during my trip at Kuantan...had to drive back with my a$$ exposed all the way on LPT highway...horrible experience there..boss also so lansi..anyways past is the past..
Finally after so long kumpul duit, finally did Option 2 with full exhaust system from extractor all the way to the tips at a reputable exhaust shop in Melaka..did a before and after dyno...result was increase by about 10whp..very satisfied with the power and sound :top: imho tho, the power increase most probably came from those high performance extractors and removal of catalytic converters..however if u change the back-box only with bolt on plug n play aftermarket exhaust, i believe there should not be any increase or decrease in power..mostly the effect will be on sound only..
Option 3, thinking of doing this initially...but found out later that this will cause loud sound in the cabin and very apparent droning effects...HM sure will bebel..but if you don't mind all this, then probably this is the best setup due to its direct flow (i stand corrected)...
anyways, happy modding all and my advise is do a proper and thorough research before committing...oh and also dont forget to change your air intake system or air filter then after that do an ECU remap...the result sure will put big smiles on your face...hehehe
