Re: Undertray for 145
Yup, My 98/99 145's got one - attatches by two reasonably sized bolts into tapped holes somewhere around the inboard end of the wishbones (well, lower links). Then two M6/M8 (can't remember) into inserts under the front bumper and some other self tappers around the wheelarch inner covers.
Inside's got some sound deadenning foam under the engine, and a multi layered heat reflector just under the exhaust (they come mighty close!) Then a cutout for that cast bridge thingy.
They're a mixed blessing (lowers the ground clearance even more as they tend to sag in the middle if you don't fiddle putting them on) but my engine bay is fairly clean. I've heard before that the fiddle putting them on and off means several have been "lost" by alfa garages...