The T-Rex is a mixed bag. On the one hand, it's relatively cheap for a battleship, and it has tons of armor. It's also one of the fastest battleships around. On the other hand, it has few large weapon mounts and even fewer point defense systems. It has no attack bonus to speak of.
The Scalar Wave Amp device will probably see very little use in an offensive capacity. It's just too slow to be useful. If you're able to park a fleet of T-Rexes over an enemy homeworld for the number of turns required to do some damage with it, why not just ground assault the base and capture it instead? Or use the Lizard ability to ignore enemy Base Shield and blow the base from orbit. The device is extremely useful to the Crystals, though. Use it to strike a deal.
The T-Rex also mounts the Gravity Well Generator device. This device is your only defense against hyperspace races, unless you can acquire a Gravitonic Mine Dropper somehow. However once some T-Rexes are flying around with Gravity Well Generators turned on, hyperjumping races like the Evil Empire or the Rebels have a real hard time: Their ships are knocked out of hyperspace and due to their low warpspeed they have no chance to get away and are an easy prey for boarding.
The T-Rex is one of the best tower, 190ly and can tow almost all ships.
 Ship Devices
 Useful Configurations
 Mostly Energy based
* Tachyon Guns have to be boosted with Exotic Techs, to be effective.
** The PD config should be chosen depending on the enemy you are facing.
*** Depending on the energy requirements use some better generators.
- It is subject to the special rules applying to ships of the Lizard Kingdom.
 See also