The version of the song featured in "The Unaired Pilot" was much slower, however, it was sped up for broadcast. An instrumental version of the original broadcast song plays over the credits to most episodes. The theme song plays after the show's satirical disclaimer is displayed on screen.
In Season One, the instrumental was originally constructed with a slightly quieter guitar and a more prominent trumpet. Up until "An Elephant Makes Love to a Pig", this version was used. In "Death", the trumpet was quieted and the guitar was made louder. In "Pinkeye", the intro was changed to include eerie Halloween sounds. For the rest of Season One until "Fourth Grade", the instrumental with the prominent guitar was utilized.
In Season Three, the boys' vocals were changed; Kyle Broflovski's voice stood out more in his and Stan's lines, and Cartman's voice was updated. Additionally, Kenny McCormick's line was completely changed, with the replacement of his lines and a higher pitch.
Over the course of the series, certain lyrics have been changed, including an entire verse, originally sung by Kenny McCormick, sung by Timmy Burch in the Season Six intro due to Kenny's temporary death in the Season Five episode "Kenny Dies". From the episode "Fourth Grade", to "Kenny Dies", a hip-hop version of the song was used, which was remixed by Paul Robb. Afterwards, they used a bluegrass remix of the song until mid-Season Ten, where the original song was remixed with "Whamola" by Les Claypool and his group, The Frog Brigade, from their album, Purple Onion.
For the special "Goth Kids 3: Dawn of the Posers", a new theme song was made specifically for the episode. The lyrics were altered to fit the personality of the characters.
From Season Six up until mid-Season Ten, as clips from numerous episodes played, the theme song showed animation director Eric Stough designing the boys with construction paper, an animation technique that was used for the very first episode, "Cartman Gets an Anal Probe".
From Season Seventeen and onwards, a 3D computer-animated version of the intro is used, and it consists of the bus driver driving past various South Park locations as the four main boys sing their lines, resembling the Season One-Four intro in many respects, with the exception of the 3D animation and "Whamola" instrumental.
In the episode “Sons A Witches”, the theme song was altered with many Halloween-themed elements added.
I'm goin' down to South Park, gonna have myself a time.
Kyle + Stan:
Friendly faces everywhere, humble folks without temptation!
I'm goin' down to South Park, gonna leave my woes behind.
Ample parking day or night, people spouting: "HOWDY, NEIGHBOR!"
I'm headin' on up to South Park, gonna see if I can't unwind.
Kenny or Timmy:
So come on down to South Park, and meet some friends of mine.
Kenny (Unaired Pilot): Our town is bigger dammit, right down to the little granite.
Kenny (S1-S2): I like girls with big fat titties, I like girls with deep vaginas!
Kenny (S3-S5; remastered S1-S2): Hey, I got a 10-inch penis, use your mouth if you wanna clean it.
Timmy (S6): Timmy, Timmy, Timmy, Timmy, Timmy, Timmy, livin' a lie TIMMY!
Kenny (S7-S10): Someday I'll be old enough to stick my dick up Britney's butt!
Kenny (S10 Episode 8-Present): I like fucking silly bitches and I know my penis likes it. (Occasionally misinterpreted as Kenny saying "Welcome to South Park" twice)
These were never censored because it was already difficult to make out.
"Goth Kids 3: Dawn of the Posers"
Goin' down to South Park
Gonna have myself a time
Michael and Henrietta:
Death and sadness everywhere
Loneliness and degradation
Goin' down to South Park
Gonna take my woes with me
Nightmares every night
Posers spouting "Let's go shopping".
Heading out to South Park
'Cause I cannot unwind
I Like spiders, loss and rain
I'm only happy when I'm in pain
So I'm goin' down to South Park... to die! (echoes at the word "die")