So your buddy has a 3D printer eh? Grab the files for the MV Gauge Holder and print yourself one. I wouldn't recommend printing in PLA, but I mean... if it deforms with heat you could just print another one, right? Run a 10mm brim on the inside and 15% infill. No supports required.
 
The FWLRtuning MV (Miata Vent) gauge holder is a clean and simple way to mount any 52mm gauge in your NA or NB MX5/Miata (1989-2005) while maintaining airflow. 3D printed in ASA, they install with a satisfying click using the same mechanism as the factory vents. Just pop your vents out and replace them with the MV.
 
If you'd like to purchase the MV printed in black ASA visit:
One-pack ($15.00 each)
Two-pack ($12.50 each)
Three-pack ($10.00 each)