I think metal scoops are awesome. a huge number of parts on the car are plastic, and they aren't doing too well after 10 to 15 years of use - the more metal the better (I worry about the plastic bits in the engine - I've replaced the sump baffle with a metal ebs unit, but the tensioner pads are a known issue and I have concerns about the plastic oil separator...). and it looks like they only reduce clearance by about 1"; no different than this:
TechnoSump
or this:
Rear Subframe Stabilizer W/ Tie Downs (Front and Rear)-Rennline, Inc.
or anyone who has put on aftermarket headers, lowered their car, or done a 996 engine swap. I do realise that the rubber ones are designed to shear off, but a thin alu part should do the same, or even better just deform so that it can be bent back afterwards. and this way you can make them as big as you want (anything that improves tranny cooling at the track is a big plus in my book) ie, perhaps rivet an additional rubber flap to the initial metal scoop, or use the provided template to make a larger scoop out of an old Tupperware tote.