I'll be going on Drag Week next year and to my understanding
its mandatory to have the class and car number on
the back window.... mine is Lexan and I want to be
able to take it off after DW is completed... how would
you suggest I do it... I dont want to put it directly
on the lexan... I'm open for ideas ... I have to be
SUPER CAREFUL with this window... I cant take it out
due to the back bars going through it

use a very thin coat of vasiline on the back of the sticker(Glue Side), as long as you dont get wet or try to wash the car to much you should be just fine. try this on a spare piece if you have some with a junk sticker just in case

Could you use the vinyl material that sticks but there is no glue? Like the kids use on a window I forget what the name of it is.

http://wallstickeroutlet.com/peel-and-stick-decals.php

something like this but not sure if it would stay put at speed.

Mike , I had new number decals made for my windows this year and to get the old ones off I just used a heat gun and warmed them up a little . They came right off.

When I have to run "temporary" stuff on my lexan on the big tire car we use painters tape, the yellow stuff. We put it on the glass, place the decal on it and then trim around the outside. It has worked well. I have had some decals peel off the margard on my windows so if it is temporary we use tape.

I know the static stickers dont stay on... I tried
using them for my dial in some years back