I think it's also for when driving in heavy rain (you take sport off which means it remains closed up to 5500rpm), where the ram air hole would send all the water in the intake.

The flap is also there for emissions cycle testing but its not needed for an MOT in this regard so can be ditched. Roof is a relatively easy change, four bolts and drilling out some spot welds on the OEM metal one and bolts and bonding for the CSL one. Windscreen type sealant works just as well as others although make sure you do a water test after. A few breakers get CSL roofs in but check to see how they have been removed before buying as if you twist the roof as part of the removal it will break down the lacer and go opaque in the sunshine. New roof from BMW is £1300 I think? We did one for an insurance claim a little while ago due to something being dropped on it by a builder.

You could fit a race roof but I wouldn't advise it, they are much thiner and not as resistant to sunshine or water.

Alex, this wouldn't make any difference. The lower air feed is always open.

This takes air under the bumper

Perhaps BMW should've linked the flap to the windscreen wipers ;)

What happens if you go over 5.5k rpm in the wet and the flap opens? Does the engine break due to hydraulic lock? Nope, it is fine...

Ah, the lower lower one. I see.;)

:thumbs:

Im looking into getting a 2005 or 2006 so it should already have the MSS54HP ECU. Questions:
Would I need a DSC reflash and the CSL SMG software even if the car is a M3 CS?
Is the M3 CS suspension the same as the M3 CSL?

Im going to have to get in touch with Evolve, I keep hearing good things about them.
Thanks

Does the wiring loom come with the CSL intake? Im lost on this.
When you say CSL software are you referring to the Alpha N or something else?
If its not to much of a bother to dig them up, I would really like to check them out, very interesting.
Thank you. :beer:

Oh, I see. Well that sucks.
Thanks for the insight. :beer:

Max - why bother with an expensve M3 CS 2005 / 2006 for? Just change the steering rack and reflash the ECU with CSL ECU / SMG ECU software.

The DSC / M track mode software / retrofit is very easy but use M3 CS algorithm. CSL one is tuned for lighter, stiffer car - the software is different. The ABS software is different and no good to a standard M3.... unless of course -unless you'e going to totally replicate every single thing... but it makes no sense tbh.

If you're interested - i have researched this subject very, very well and don't mind sharing the knowledge.

First off - what will you use the car for? Track days? Mixture of track days / road? or you just fancy having a CSL?

I have decided to install all the best CSL bits but leave the toys and comforts. I'm even wondering if i should put back my standard M3 seats but re - trim them so the top looks like the seats from an M6. I drive so little and when i do - it's a road.... but i do like this sprty car feeling the Recar seats give you..... i'm still undecided.

I have Recaros but was thinking of Recaro Sportster CS (the BMW Performance ones)

I'll dig some diagrams for you. I've got all the original E46 M3 options bought and ready to install too. Also little things like 5000K xenons, illuminated door sills, Alpine iPod connections, JL sound upgrade, blutooth and so on and on. Loads of other things in short.

Got to be miles easier to get in to a CS that to buy a new ECU, get it coded, new steering rack new DSC module (extra pin I believe?), new steering wheel panel, all the labour, CSL brakes already on it.

Got to be a much, much easier and cheaper starting point, also retain value better, if for example you spend money upgrading the ECU to a later one you may as well burn that money as far as getting anything back come resale.