Your other thread with the same question. Notice that both threads have similar suggestions for the work that can be done on the cylider heads.
As to getting even more power out of the Liberty...
Here's an article on getting more power out of the KJ:
KY Liberty's thread on power
Here's another good topic on adding Cam's to the Liberty:
Camshaft Topics
Boilermakers thread on the
B&G Flash for the computer.
There is loads of information on methods available to us for increasing the power output on the 3.7L work horse.