Has anyone fitted a hayward & scott straight through mid section, after the cat & retained the standard sti rear box on a 2.5 sti ? ? Did it make the car any louder ? Perform better ? Etc or does it need a h&s or prodrive rear box as well ?

 

I've just replaced mid section and backbox together on my 06 STI. If you searched the forums you'd probably find the consensus being tht the mid section is the most restrictive part of the system, so if you do just replace that bit you will get an increase in power, and probably a small noise increase too.

I can recommend the H&S stuff though, that's what i put on. No idea on difference in power as I did it as soon as run in so didn't do a before and after comparison. Sounds great though.

 

i did the same as Pete and replaced both the centre section for a straight through and a backbox (group N from TSL) and got back the burble and a good performance increase too.

 

Thanks for the replys guys
How loud are your cars now ? Don't want to upset the whole street or deafen the kids on a long motorway run
cheers

 

i have since changed mine but with that section on it was fine - no motorway drone and certainly not waking the neighbours

 

Did it get any of the flat4 burble that we all love so much back or just louder ? What rear box did you later put on ?