Well if its specs your looking for why didnt you ask?
Usually the racquet is based upon three things:
Weight of the racquet
Size of the head
Comp
and to a lesser extent. the factory string,
Most racquets tend to improve these four aspects of a racquet... so for example you had the:
Dunlop areogel mfil pro and then the aerogel 4d.. surely theres going to be a difference..?
Different racquets are made for different purposes. Just like the aerogel ultra, that racquet was perfect for drop shots and ccatching the nick, whereas the aerogel pro is more of a sturdy racquet allowing you to hit the ball cleaner when going for a drive..
Usually they tend to make products better, therefore the price being higher.. like any company would
And a final point, NO-ONE can hit a ball hard enough in a proper squash match through personal experience..