Do LED drop ins overheat in plastic lights??

Can I run Cree or SSC drop ins in stuff like a SF G2 or Brinkman Maxfire without concerns over led failure?

Seems to me that someone somewhere said they would overheat and poop out on you.

I'm asking because I have several friends with plastic (G2) lights and since they over payed they refuse to just buy a new $20 China light. :shakehead

I really like the SSC drop ins because the color is nicer than the Crees at the same price, plus the floody-ness is kind of nice too.

would like empirical data on full length runs, 3.7 or 7.4v used, specific drop in, specific light, ect...

I have several different drop ins that I use in my G2 with no problems. I don't usually run the lights for one hour at a time, but the drop in provides much of the heat sinking needed.
I especially like the Seoul drop in: http://www.dealextreme.com/details.dx/sku.4068
It gives a nice broad spot that blends into the spill...great for indoors- decent for outdoors. Plenty bright for all but the few who need 240 lumens!
Remember- many drop ins need a bit of tweaking ...some need the ouside spring- some don't. Some don't fit perfectly...
I had to cut one loop of wire, the size of the battery tube, to get contact with my drop in. Once figured out- this is my favorite.

we, with our very limited eyes, would only notice the unevitable degradation of any of the "usual" inserts (high powered inserts!), when it happens very quick --> pretty none of the inserts is this bad.

but it is in the modders brain, that the heat has to be moved away, something that happens not good with an insert, and even worse in a plastic light.

Example: I have a homemade 6P that is 18650d and Creed and an insert that is inside a leefbody 2 18650 body.
the single light draws about 1 A, the double battery one draws about 500 mA --> means both give the same current to the led (more or less, of course).
While the very good sinked 6P gets hot within 10 mins of use, the insert can only give the heat to the leefbody at the very front end, where the thin end of the reflector meets with the metal.
It is difficult to feel the warmth, even when just gripping the head.

As both lights produce the SAME amount of heat, but only one puts it to the outside, the other one not, I am pretty sure, which one is more easy to the led.

... see an insert the same as an incan bulb --> cheap and when its so bad to notice, get a new one.

I think it would be reasonable to run one of the lower drive current aftermarket modules in a plastic light. Malkoff makes one with excellent run time.

http://www.malkoffdevices.com/shop/index.php?main_page=product_info&products_id=20

"The output is 140+/- lumens. The current draw is approximately 350ma at 6 volts. The runtime is approximately 4 1/2 hours on 2 CR123 primary batteries."

Even the surefire OEM 80 lumen module would overheat in plastic G2, and step down to lower output to cope with it, so I'd bet the higher output aftermarket ones will too. However I don't think most of the aftermarket ones have a heat sensor, so they'll probably cook themselves.