Wogster

Saddles (don't call it a seat, unless you want people to think you don't know what your talking about), are an individual kind of thing. Everyone has a slightly different rear end, and one person will try a certain saddle, and think it's perfect, another person (same saddle) will think it a medieval torture device. The key is that there are two bones in your butt, these are often termed the sit bones, you should have your saddle support on those bones, to narrow a saddle and your sitting on the soft tissues in between, which leads to numbness, this is one of the reasons many saddles now have depressions or cut outs in the middle. Too wide a saddle and you often get chaffing issues, which causes pain. Now, either numbness or pain, is likely to severely reduce ride time.

There are two ways to measure your butt, if there is a Specialized dealer nearby, call and see if they have a butt-o-meter, this will give an actual measurement, get the numbers, and look at the collection of saddles the dealer has. Another way to get a measurement, is to take several layers of paper towel, the top one should be slightly damp, put them on a hard chair, and sit, now peel off the first couple of layers, and you should see two damp spots, measure them centre to centre this measurement is what you want.
Saddles come in various widths, from around 120mm to about 160mm pick one closest to your butt width.

Second item, it depends on your bike and riding style, a drop bar road bike, typically has a longer, narrower front then a saddle intended for city pootling, best saddles ar a Brooks of England saddle, they have been making them for over 140 years, not cheap, but they do work well, just make sure you get the right size.