I am considering changing my stock air filter with either a BMC, K&N, or EVO after I installed my Softronic Plenum and flash. I have read somewhere on the site that no difference was seen by having one of these filters combined with the Softronic's plenum and flash over stock. I would like people to comment on their findings with their air filter and Softronic's mod combinations.

I am particularly intersted in anyone that installed one of these filters after doing the softronics plenum and flash, with no other mods.

I suppose people can also comment on desnorking in combination with the above combinations as well.

I did the following in this order. Each had ample time in between them for butt-dyno evaluation. I have a place where I test my trap speed. (Stop to a marker. Stock was ~100 mph.)

1. IPD plenum.
2. Milltek catback exhaust.
3. Softronic reflash with sport turned on. (No sport previously.)
4. Desnorked.
5. EVO K&N intake.

After #1: A noticable improvement but not eye-opening. Car was a little green and I didn't have too many miles under my belt yet.
After #2: A really noticable almost "huge" improvement. Really seemed to wake up the car. It felt like the stock exhuast was choking the IPD plenumn. Car was notible faster. Car ran my trap @ ~ 103-104.
After #3: A nice noticable gain again. Sport was surprisingly nice. The pull in the upper revs was a huge difference. The ability to rev to 7700 is cool too. Car ran the trap at ~ 106. Power is more difficult to get down at the start.
After #4: Didn't notice anything. Was expecting more noise but didn't sound any different. The exhaust must drown out any noise changes. Trap speed still ~ 106.
After #5: A slight change in the upper rpm's. Not really noticable. Was expecting a large growl under accelleration, but frankly I was a little disapointed in the noise. I guess the exhaust drowns out the sound. Trap speed ~ 106.

The software seemed to adapt and adjust after each upgrade. The only thing I've noticed on the software is that if you don't have your shifting/gassing timing just perfect on a full throttle high rpm upshift it seems to not have the fueling just right. What I mean is that you have to be perfect on the throttle application after the shift in order for it to be fueled properly. I was having a tendancy to be a bit early. It seems more aggressive on the delivery than the stock map which I think allowed for some throttle application sloppiness. I hope that made sense, it is kind of hard to explain.

By far the most gains I felt were from the exhaust, plenumn, and the software.

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Nov 16, 2007 build:
'08 CS Midnight blue metallic
Black sport seats
Delete model designation
Fire extinguisher
Floor mats
Sport steering wheel

Other car of interest: '86 Guards/black 951

This is exactly the type of info I am looking for. Anyone else have any feedback?

We have discussed the air filter mods a bunch of times. There are those who believe and a bunch of us who do not. The manufactures are not willing to publish specific claims for specific models so that is at minimum a flag. I would suggest reading those threads before deciding. The one really big warning is that the oil based filters can be over oiled and damage sensors. My own observation over a long time period of Porsche ownership is that people forget to clean them and wind up losing HP as they get dirty so if you go that route you need a good call up system.

At the risk of starting a war, stay away from the "fancy" type air filters....the one or two HP gain (if even that can be verified) is not worth the extra dirt these filters let into your $$$ engine. Keep the stock filter and just change it every 10k miles to make sure it's nice and clean,....it's not a limiting factor for the CS.

The other perf mods mentioned, exhaust, IPD and Softronic are verified HP producers.

At what rpm did you shift to get 106?

Changing the air filter in a car to gain HP is a joke. If you don't believe me just ask TPC. Most aftermarket filters will probably lose HP.