The catco part# cto-4087 is a 12.5" x 2.5" cat. converter. Could I use that one instead of using a cto-6906 and cutting off .75" off each end? The info about them is on summit's website under direct and universal fit catco cats. This is going to go on my '92 se-r. TIA.

yes...you can use any cat on your car as long as theres one there. random cats even makes one in a 3in diameter for the turbo guys, big v8s, etc. so, yes...you can use it.