by Hans Efde » Tue Apr 29, 2014 7:57 am
Mike Perkins had an aluminium plate as rear undertray on one of his older Midasses. Moneywise it's better to buy them from Alternative Cars. I bought them from him since there is not too much saved when going to the trouble of building them yourself in composites. The only way to build them cheap is if you can get some alu sheet cheap.
Bolting them to the car is straight forward. They bolt or screw to the bumper (there's a recess) and the bottom to the car with in total 11 to 12 screws per undertray. The Corby factory used to use parkers but they will run loose quickly. On my first car the aft one came loose, luckily at low speed without damage. Alternative Cars sells a mounting kit with stainless rivnutsor anchor nuts, but you need a special tool for it. I used rubber nuts to fasten mine. No special tools needed, they won't run loose and they won't rust. You'll find them on Ebay. Don't forget to use large washers under the bolt head.