I am on my way to make another upgrade.
I have a K&N drop-in, a HKS dragger II catback, an Autronic replacement board and the MR is tuned on 1.55Bar peak and 1.5Bar stady boost.

I now want to instal a high flow cat.
I have the possibility to get an Ultimate-racing Highflow cat (2.5'' as I use the stock DP) for a very reasonable price. I have seen, they do not use a metallic core, but a ceramic one.

Can anybody answer the following questions?
- Is it a real improvement over stock concerning backpressure and spool-up?
- How much gain can I expect?
- How much HP can this cat cope with?

Thanks a lot!
Kunz

 

I heard something like 10-15whp with a high flow cat. Better spool-up too.

 

I have the 3' and love it.

Netted me 110 mph 1/4 on 93oct with 19 psi.

No cel with anti-fouler mod. 2+ years running.