If you have the same pressure front and rear you will have the front tyre less squished (technical term) than the rear when in use. You need about 10psi less in the front. And unless you are particularly heavy you do not need to inflate to 100psi+, unless you want to shake your fillings loose. With Grand Prix 4 Seasons (25mm) I have about 95psi rear and 85psi front, and having them any firmer only makes me back off on coarse road surfaces (i.e. most of the time).
To get the right tyre pressure for you, first find a quiet bit of road with a uniform surface of coarse chippings. Inflate your tyres to max pressure, then ride around and feel the vibration in the bars and saddle. Then stop and let out some air. Ride around a bit more. Repeat as many times as you need, possibly pumping more air in if necessary, until you feel that you have found the right pressures. Then measure the pressures with a gauge that you trust, and make a record for future reference. Takes about 20 minutes and is well worth while.