ENTERING / EXITING MEXICO AS A TOURIST ?

I have a question about tourist rules. I would like to spend mid-June thru mid-September in Mexico. Also mid-December thru mid-March. I would be driving, crossing at Laredo on both trips. Does Mexican law allow this?

Also, should I need to make an unexpected trip North (funeral, for example), could I fly out and back on my visa?

I've heard your visa is tied to your car; if you drive in you have to drive out. Also that you get only one entrance in a 365 day period. But I would appreciate Spencer's expert advice.

While I'm at it, ThankYou!, Spencer, for all your time and expertise on this and other boards. When I get down there, I'm going to look you up and buy you a drink!