Borla and highflow cats

[Viper Nut]

I have a Gen 3 with a Borla mufflers and set of high flow (mid cat delete) cats. I am not sure of the make of cats. Anyhow I bought the car in this configuration and cannot stand the sound, noise level and drone. So I picked up a complete '08 system from the exhaust manifolds back. I pulled the sills yesterday not knowing what I would find underneath. I originally thought it was just a cat back change, not knowing that that the cats had also been changed / deleted.

My original intention was to just change the mufflers and be done. Now I am concerned that the cats may be as much to blame as the borla's. Then the other concern that I have is if I put the cats from the Gen 4 on will interior be too hot in the summer and will they even fit?


The car is toy/cruiser. I live in the mountains and like to play. However it's a car that my wife and I will take on some scenic cruises and don't want to be too road weary at the end of the day. We were in the car for seven hours on drive home when I purchased it and the drone was so bad that it was hard to carry on a conversation....



So here are the questions..

What do you think is causing the problem. The cats or the Borla's? If I change only the mufflers should this take care of the noise level and drone or will I have change it back to the stock (Gen 4 as I don't have the orig Gen 3's) cats too? Will the Gen 4 cats even work?

By changing to the Gen 4 cats and mufflers will I make the interior too hot for summer cruising? Will the A/C work efficiently? People with stock Gen 4's please chime in.

Thank You for putting up with my newbie questions......

 

[FrgMstr]

I would suggest the Borla's are more the cause of your issue. Went with Corsa exhaust on my Gen III because I heard so many people talk about drone. If I were you, I would throw the new catbacks on and run it around and see what it sounds like. Dunno on the rest of your questions. I do have a Gen IV take-off catbaks if you are looking to buy.

 

[2easy]

I have an 03 and did what you are doing with the 08 system. I removed the old 03 system with the crossovers from the stock manifolds back and replaced with the 08 cats and mufflers. I hollowed out the cats for more sound which, is not what you are looking for, but to answer your question, yes they will fit. Both of your HF cats and borla exhaust will increase the noise level. Corsa will get rid of the drone completely, or go back to the 03 set up, less the crossover (it adds weight and a ton of heat) I have my original exhausts and a new set of 08 cats if you are interested. I would consider a trade for your high flows and borla. I love loud, and unlike you, not being able to hear my wife is a bonus!!! lol. PM me if interested.

 

[cubican]

Corsa is the way to go and you will have no drone at all, the borlas will have some drone but if you put your stock cats back on they will work fine some minor drone.

 

[Viper Nut]

Thank You Gentlemen. Any other input....