Grand Theft Auto IV Tips

[Glitch]Fall Through Building
I just discovered a glitch while just playing around with a six star wanted level. I was on top of the safe house you get from playboy, just trying to see if I can spawn vehicles on top of the roof. I found out that if you go to the edge of the roof and spawn something it will stay in the air, it won't fall unless you shoot it or something. The second glitch I found was I spawned an FBI buffalo on top of the roof with no problems except when I tried to get in I instantly feel through the building and I thought I was gonna die, but I just ended up on the street behind the safe house with no health damage.