To Rob houses you have to find a truck like the one you used in the mission. I haven't been able to find it yet. I've been too busy provoking gang wars and expanding my turf
I hit a bug in the car mod garage and got a max insane jump of 9480.something feet. It gave me about $2000+ which reinbursed me for the paint job I accidently bought
I got 1700 on the hydraulics mission. I kinda quit trying near the end because I knew I had it won.
One other very weird thing happened to me. I had just finished a mission, I hopped in a car and started to take off and an airplane(looked like a ww2 fighter) crashed into the road and corner of a building destroying a car and burned up. I looked in my stats later on and noticed I got credit for destroying a plane