You can put a good amount of air in the tire. An under inflated tire is more dangerous than an over inflated one. The blow-out pressure on a tire is somewhere between 100psi and 200psi. After around 55 or so psi there is no gain in FE so its pointless to go higher than that. Just to note you are more likely to blow your tire at 30psi than 50psi when taking a corner or driving on the highway.

Pros of Higher presure.
1) Faster stopping times.
2) Less hydroplaining
3) Better FE
4) Higher load carrying capacity

Cons:
1) possibly uneaven wear on your tires (check them regularly for wear and reduce preasure as needed)
2) longer stopping distance in snow.
3) rougher ride (can cause suspension to wear out quicker)

My hydroponics experiment

You ever notice how hard it is to lip read cartoon characters?
"Crazy is what the sane call Delta Flyer"