If you haven't done so already, I suggest you check this out:
Fourtitude Project TT

 

Joe@Fourtitude"putting down just under 205 whp at 4,750 rpms and 238 ft. lbs of torque at 3,000 rpms. This was an increase of almost 8 whp and 22 ft. lbs. of torque over our previous best runs."

I would say that is a good gain for a catback alone and still running a stock dp.

then with the dp with cat "The best run of the day netted a 9.3 hp and 19.3 ft. lb. peak gain at the wheels. Not only did it yield these peak gains, but power was increased over the entire RPM range."

I would say catback's AND dp's make signifact gains on there own.

 

Alright downpipe is here and going in on Thursday (having a local audi performance shop do it). I have seen the"how 2's"and it doesn't seem thatbad but I really don't have the time and I want it on NOW.I am looking into picking upa catback this week...and this is where I am running into problems. I have it narrowed down to Milltek, APR and Borla.
WithDSM's I have been taught that a 3" system is the best, at least for the 4G63. After spending hours reading it seems this maybe a little overkill for the 1.8l engine w/ the K04.....how trues is this? Cincy...you there??
I currently want to max out the stock turbo. If do decide to go with a bigger turbo setup (in reality at least a 1yr)...would the Borla or Milltech piping suffice? It seems goingfrom a large 3" dp w/ 3" cat to smaller piping will create a restriction in gas flow, or is this negated by the gas temps being cooler and denser down the line?

For the 3" system I have found the APR 3" catback (finally) and wondering if I should just go with that for a full 3" exhaust. The systems are around$300 of one another which isn't that much. I also don't want something that drones and that's what I am afraid of with the 3" on this engine. The Borla right now sounds the best to me. Please chip in with your opinions. Thanks!!

 

I have the VF engineering pendelum mount. Will this even fit with the 42dd? Its a little bigger than the stock dogbone mount.

 

Most 225 exhaust seem to be 2.75" and that wont harm anything going down 1/4". You deffenitaly wont see any gain in going with a 3" over it either since it flows more than a ko4 can provide. ALso there is a guy on vortex making 500whp on just a 2.5" exhaust with a 3076r if that tells you anything. So you will be fine going with a Borla or blueflame/foge exhaust.

Also the vf mount will fit, but not really needed since you can swap in bushings for far less and get the same effect.

 

Got it for free, you cant get any cheaper than that.

 

Best deal in town right there! I was speaking for us less unfortunate ones [8D]

 

Thanks for the input...just ordered the Borla. I spoke to the guys over at APR.....VERY honest and helpful. They did confirm the part number of their 3" catback from where I found it. He was upfront and told me that the full 3" system, even tho not mated to their 3" dp would be very LOUD. They have had people buy the system and not happy with the noise level it created and wanted to be upfront with me. That my friend, makes APR someone to do business with in the future! Someone honest and straight forward. I asked about the performance hit with the bottle neck of the 3"dp to the 2.5 catback. He stated that there would be some power lose but not anything too drastic BUT noticeable.I can't waitto get the setup on, DP on this Thursday and I will do the catback myself.Coilovers......next!

 

I have the APR full system and it is a very nice sounding system. I would hardly call it loud. It has a nice rumble at idle and under full acceleration has a very throaty snarl through the gears. My only complaint is it is a little boomy on the freeway. I experienced the same thing with my Miata when I went to the Borla cat-back on that car. I solved the problem by laying down a layer Dynamat on the trunk floor.

 

Yes I guess loud is in the perspective of the listener. The sound bites that I heard I didn't care for but in the same sentence......no one thought the exhaust "really" sounded like that at all. It even had APR commenting on it. I am speaking of the 'tube video.
I chose to heed APR's staff's warning. I have spent 1k on an Apexi Dunk catback for my eclipse ...when I got it on there....I was not happy, it was too loud. I think this time around I am playing it a little safer...abalance betweensound and power. Across all theboards... Borla was always up there in the topexhausts mentioned across all the Audi vehicles.

LOL, I was actually hunting around for you earlier to see if you had any clips. You have been one of the few on this board that I have seen with this exhaust.