My only suggestion would be – what about looking towards weight reduction and/or Aero.
Weight reduction: 2 piece front/rear rotors, Aluminum parts, etc.
Hopefully I am not taking too much liberty with your statement of “Open to suggestions” because.. well, yeah, below. lol.
Aero: Front wheel well aero-curtain, functional rear diffuser, etc. (Yes it is generally a bad idea/net negative to start slapping on Aero-mods without proper testing but rough testing can be done DIY to gain an idea.)
Rear diffuser: One would have to be mindful of exhaust/muffler temperatures but brackets can be made to attach connection points where the rear anti-roll bar connects. the rear connection point could be done by creating brackets to bolt into the rear bumper support.
I made the brackets and a diffuser a few years back out of sheet metal but it was horribly ugly. I hadn’t made any consideration for muffler/exhaust heat so I wasn’t comfortable leaving it on. (On purpose, it was simply a fitment proof of concept for myself.)
Aero-curtain: what about adding an aero-skirt to the front wheel well or potentially even if it just serves as engine bay ventilation? Many vehicles these days have them and they really did not become super-prevalent until a few years after the C30 ended production.
There is a relatively open path between the fog light cover and the front wheel wells. You probably wouldn’t want to run them without ducting to direct this air to the vents as it could increase engine bay pressure thus reducing radiator flow. (the pre-facelift c30 bumper lends itself well to this, the face-lift bumper is much smoother/rounded and, in assumption, unlikely to benefit if this is a benefit at all.)
(note: none of these images are mine they are simply for explanation.)
Originally Posted by mcrews THIS! “Back in the day”, front ducts were for cooling the brakes. Not just back in the day. The current Viper
ecomodder.com
However I have wondered, in the event this is a net benefit for drag, or if simply for brake cooling so you don’t care as much about drag – if one could include a secondary inlet inside the engine bay that would pull hot engine bay air out similar to how an air-amplifier works with the venturi effect. Yes the image below is of a pressure washer but the principle-idea is the same as what I mean. High velocity fluid moving through a tube will cause a suction force on an additional tube. But instead of water and sand – think of the high-velocity air moving through a tube with a angled connection that would draw in hot engine bay air to be expelled at the front of the wheel well. Speaking generally, again, there is often a low pressure zone at the front of the wheel well and areas of high-pressure at the top and rear.
(Yes yes I know that in general theory high-velocity air often means lower pressure but I am not an fluid-dynamics engineer. )
I’m hoping to experiment with it some this Fall once I have time.