Hmm. I have never cut that kind of plastic on a chop saw, but I have cut acrylic on a table saw. Feeding slowly with a fine blade is the key to success. I highly recommend covering the cut line with masking tape to anyone that tries it with any kind of large circular blade.

Bull in a China chop!
 

I agree, using a chop saw smells like disaster. Fine for pvc, abs, etc. but not ideal for 30yr old tortured plastic with no will to live?

Smaller type cutting tools reign for this application. Put the piece in an xyz vise and rig the dremel. You got your straight cut and rate control. Done.

Good suggestion on the masking tape. You could also try aiming compressed air (pc duster/shop air) across the contact area to deal with heat.

Heck, if you have access to one, a cnc or even a waterjet might be the best solution.

Piece mentioned in post #28 is attached for reference. Good luck putting a large blade to a sexy curve like that.

MBZ123

I'm in the habit of grabbing everything of value at the salvage yard these days for when the parts are not available. Around here the stream of junk ones seems to be slowly drying up. Except VS tech. Not sure how he does it man! I'm takin the day off work to go out across the state to a 240 that just showed up on the radar. I'm squirelling quite the impressive storage room of parts...

Ive got some wagon tail lights ,$30 each if you interested>,also have the luggage rack bars $70 for 2.

... I buy entire cars when I see them...:D

I will take the passenger taillight. PM sent. Tks

The most effective way to do it w/o major damage would probably be baking it. Read this http://http://clubsciontc.com/forums/diy-install-guides-23/diy-how-to-bake-open-tail-light-fix-tyc-tail-light-46447/

I used to work at a sign shop and we made signs with acrylic, it is virtually impossible to mechanically cut acrylic with out loosing material in the process so it will probably not fit/seal correctly again after cutting. Just my $.02 Hope it helps.

Club Scion tC - Forums - DIY: How to Bake/Open Tail Light/Fix TYC Tail Light
For some reason the link above didn't work so here it is again. Google "baking a tail light" and you will get a lot of info about it.