There's a homage to The Texas Chain Saw Massacre (1974) regarding each film's leading ladies Erin (2003) and Sally (original). In the remake, Erin pulls out a knife to unpick a lock. When asked where she got it from, she replies "from my brother." In the original Texas Chainsaw Massacre, Sally's brother Franklin is obsessed with his knife, and at one point in the film gives it to Sally. She never returns it.
A then-unknown John Larroquette provided the narration in the original The Texas Chain Saw Massacre (1974). Despite becoming a distinguished actor in the years since, he happily agreed to reprise his role for the remake.
During the scene in the van with R. Lee Ermey (The Sheriff) and Jonathan Tucker (Morgan), Tucker forced the gun down his throat in order to make himself vomit every take. If you watch carefully you can see him spit the vomit out of his mouth in the scene.
In the third movie of TCM that came out in 1990 there was supposed to be a scene where Leatherface takes off his mask, but to keep the R rating they had to cut it out. In this movie, that scene is re-shot and seen.
In the original script, the character Jedidiah was going to wear a Felix the Cat T-shirt throughout the movie. This was later scrapped because the copyright holders of Felix the Cat wouldn't allow it. However, the novelization of the movie features the character wearing the shirt. Also, Jedidiah was going to be killed by Leatherface by slicing his chainsaw through his back because he let Erin and Morgan go. This was later scrapped because the filmmakers thought it was too intense.
While the film's introduction and ending are tailored to appear to be based on a series of true events, the film's plot is a complete work of fiction. The film is inspired by the murderous acts of Ed Gein, a Wisconsin-based serial killer that was infamous for exhuming corpses as well as decorating his home with the body parts of his victims. Gein also confessed to wearing the tanned skin of women as a suit.
The trivia items below may give away important plot points.
To avoid an NC-17 rating in the USA, the more graphic shots of Morgan's death were cut. The original version of the scene featured the shot of the chainsaw slicing into his crotch and then having intestines and blood falling out of him. The cut version cuts away when the chainsaw is about to cut him and totally cuts out the intestines falling from his body. The hitchhiker death scene was also cut severely. The original scene has her ear flying off of her head and blood and brain matter being more dark in color and more in amount flying out of her head.
Some of the big plot changes made in the remake: 1. It is actually not mentioned nor implied that the family is cannibalist. One of the symbols of the TCM movies was the big dinner scene where all the family tries to eat their victims. 2. The whole family has changed. Now there are 7 members of the family, plus famous "grandpa" from the first four movies is not included here.
Kemper's death was originally slightly more graphic: after Leatherface hits him in the back of the head with the sledgehammer, he drops to the floor gasping and convulsing with blood pouring out of his head. Pepper's death was also more graphic, originally Leatherface swipes the chainsaw down into her cutting into her stomach. In the final cut of the film the impact is off-screen(you only see Leatherface swipe the chainsaw down, and you hear it cutting into her, with feathers from her jacket floating in the air.