It is made clear that Crichton's brain is far more advanced than Twiki's and that Crichton was the only one who could have performed the repairs in time. However because his brain got dented, they had to put Twiki's brain in Crichton's body. Therefore the repair abilities built into Crichton must have been in his extensors rather than his brain, so Crichton's body is also more advanced than Twiki's.
The combination robot (Crichton's body with Twiki's brain) exhibits an entirely new—and generic—personality and is called TWKE4 (pronounced "T-W-K-E-4", not "Twiki 4" despite the similarity).
Goof: The inside of Twiki's head (which contains a positronic brain) looks nothing like it did in the previous episode (standard TV sci-fi electronics).
Twiki: He hurt his head... he's dented!
Crichton: Everywhere that Mary go the lamb was... lamb was... lamb was...
Hawk: I have never seen anything quite like them.
Buck: I have. They use to hang out with a very pretty lady named Snow White.
Buck: Crichton, one of these days you are going to say the wrong thing at the wrong time to the right person and they're going to turn your knob, you know what I mean?
Crichton: Knob? Knob? I have no knobs.
Buck: Well, you get into the ship right now or I will show you you have knobs in the most unexpected places.
Buck: What's he doing here? (referring to Crichton)
Crichton: Crichton is here, as usual, to fill the gaps of human ignorance.
If you were wonderdering where you have seen actor Billy Curtis (General Vroomak) before he has had parts in many TV shows and movies in the past including his most famous part in The Wizard of Oz as the "Munchkin City Father".
It is explained that Twiki and Crichton have positronic brains. Science fiction writer Isaac Asimov first conceived of the idea as a way to provide robots with advanced artificial intelligence and consciousness. Also, Admiral Asimov is said to be a descendant of Isaac, however he did not create the robots (Twiki was manufactured at the Ambuquad factory and later helped Doctor Goodfellow create Crichton.)