I used a heat gun on high and it worked well, but the heat did melt some of the lettering, so it won't be very easy to glue it back on should I want to. Be patient and work slowly and you shouldn't have any problems.
Pretty easy just need some fishing line/dental floss, heat gun/hair dryer and some kind of solvent, in my case i used wd-40. Just heat it up and get the line behind it and in a sawing motion cut through adhesive. Dont think you would be able to reuse them since most of the adhesive will be left on the back thats why u need the wd-40.
If its leased just use some glue (not really glue but something like that, you can get it from autozone) and stick them back on....Like you said, it's leased. I'm actually going to put my back on but spell "Subie", kinda corny but whatever
they make this velcro-ish stuff that's actually the same on each end (not one fuzzy and one hooks) -- it's plastic... it's like industrial strength.... they call it fastener tape or something. really awesome to keep interior panels from vibrating. I used it on another car to re-attach the plastic pieces that surrounded my sun roof (the double sided tape they were attached with wore out)
like I said, it's LIKE velcro but not. it's only one kind of thing... a bunch of "T"/umbrella shaped teeth that all interlock.