Which is best for performance?

 

Under 350bhp, panel.

 

Ok. Which panel filter is the best to go for?

 

Not much between them TBH. Green, K&N or JR Racing are all good. STi one is serviceable so you'd need a new one at 40 quid each time, the others are lifetime items. ScoobyMag and Harvey did some testing and found that there isn't much available from any of them, with the STi being the worst and the OE paper item doing very well. Prodrive had similar findings which is why they don't bother marketing any Subaru intake products.

I/K's again offer little until other mods make the extra air necessary, as I said, at least 350bhp, maybe over 400. With them comes other issues such as MAF failure due to vibration and reduced performance due to drawing in engine bay air and raising intake temps, unless you sort a cold air feed and some isolation.

Personally, I had a JR and removed the intake resonator and ram-air scoop and I felt it spooled up a little quicker. With the intake box drawing cool air from the wing it also made the OE recirc DV more audible on changes, and produced some intake roar. Never RR'd it to see if there were any performance benefits.

 

Thanks a lot. Thats really helpful