Ok, now I get what you're saying, but I've read numerous threads and people saying exactly like you're saying about not having time to get to 100% or they don't like to collect the space ship parts, submarine parts, letter scraps, etc, but that imo is the whole point of GTA games. I've been playing since GTA III and a big aspect of these games is getting to 100% completion without using cheats or glitches. Like Vice City, for instance, why would they give you infinite ammo at 13% complete? The GOOD things only happen AT THE END of the game. It's much more wiser to SAVE all the money you have WITHOUT buying any vehicles so when you do the Lester missions at the end, you can invest all your money in stocks and double, possibly TRIPLE your money. There is numerous threads on how to do this, and I did it myself back in October. The game was designed to make you wait until the end it seems to buy vehicles, all the properties, all guns and ammo, mod every car you own, buy all the boats, planes, helicopters, etc.
It just doesn't seem logical to me to buy vehicles early on screwing up the big money to come in the end. It also doesn't seem logical to drive cars to missions, knowing that the cut scenes and loading of certain things makes your vehicles disappear. It doesn't seem logical that if people knew this for months, why they continue doing these things like driving their modded vehicles to missions and such.
It feels much more appreciated when you have 1 or 2 billion dollars per character and at the very end once 100% is done and won't need to concentrate on that, to THEN build your garages/safehouse garages/impound garages collections. And if you REALLY need to buy cars early on, or mod them early on, KEEP them in your garage until the end. Don't take them out, since Rockstar's flaws in this game will make vehicles disappear. With all thisbeing said, I only lost the Space Docker back in September when the glitch/bug WAS known, and Rockstar claimed to fix that back in Patch 1.02 or .03. Ever since, I have not had ANY problems, and autosave is ALSO turned OFF.