Mine came off upon my purchase of the car 1 year ago, after spending the former 18 years of the car's life on, in the relatively warm Aussie climate. The engine, although low-miles, received a clean bill of health on compression testing at PPI, and still runs very well.
The undertray had more-or-less perished from having served its intended function as a drip-tray for hot oil
, although the oils leaks had obviously been fixed previously because she continues to be
drizabone.
I don't see the need for any fancy thermal testing - the tray either increases engine temps, or doesn't. Therefore, there's no harm in removing it. The only potential advantage to it would be an
aero effect, which if present would prob be fairly minimal anyway, and certainly not relevant at the speeds that I drive.
(Although, I've got a spare tray stored away for concours...)
