Mark, that is the issue us diecast guys and gals face...to open and display or not. In the long run keeping the package will increase the value by 50% many years down the road. GreenLight makes very sturdy packaging so that's a plus. I sometimes buy multiples so I can one up, these Gulf's are pricey and some are limited to under 3,000 units for the whole planet. Making them an instant collectible. They just came out so I bought at a decent price, they will start to double next year when supplies run low.
The Johnny Lightening 'Gone Fishin' series with the Olds VistaCruiser in black and red with fishing boat is already getting scarce with less than 2,000 copies, of course I have both
I always try to keep a few Hot Wheels and Matchbox in the original cards, who knows where the market will go $$ wise in the future, I have a feel for some of these. Glad I did, some have gone from just a $1 car or truck to over $8 in a year, who knows where 20 years from now?
Just a tip for someone just getting into this, the Matchbox '71 Skyline GTX is a very hot item. It comes in two versions called 'racing seat belts' and without belts, the neat thing is each has a different engine you can't see under a hood that does not open. Crazy cool stuff! Then you have two different cards, one has the blue car (more common here in North America) and a silver car. I bought a set online with 2 vari's of each blue car card and one each in the silver car card for a very reasonable price. The casting on this car is amazing, very true to the original 1:1, great detail that begs to be detailed out with some paint and chrome foil, and maybe a wheel swap.