Do not buy the antenna from Cessna (Spectrum, Hill, whomever)! It is basically identical to the Comant CI-101. There is no reason to pay Cessna "middle-man" prices for this.
CI-105? ALL tansponder antennas double as DME antennas. 400 mph? No!
The CI-101 is a perfect replacement, but Spruce advertises them online for $94.25, not $47.
http://www.aircraftspruce.com/catalog/avpages/com_trans.dmeants.phpThe Comant CI-101 should sell for about $69.
http://www.gulf-coast-avionics.com/detail.asp?id=4397http://www.peninsulaavionics.com/item323.htmThe fairing air scoop pn 0452200-1 is only available from a Cessna dealer (Hill, Spectrum, etc.). The doubler pn 0452002-30 is the reinforcement on the inside of the cowling for riveting the fairing in place.
The exhaust doubler is just a round reinforcement for the exhaust hole in the cowling, and can be fabricated from aluminum sheet, using the old doubler as a template.