The costume grants no additional features. It does make Spider-Man bulletproof, however, with a cost at his speed and jumping level since the weight of the costume slows Peter/Spider-Man down.
History
When the New Enforcers attacked New York using high caliber fire-arms, Spider-Man created a suit of "Spider-Armor". Composed of a pseudo-metallic compound Peter Parker developed at Empire State University, the suit slowed him down, but allowed him to be bullet proof. During battle, the suit was mostly destroyed by acid.
In the series finale of the Spider-Man (1994 TV series) in which Spider-Man meets Spider-Men from parallel universes in the episode "Spider Wars", he meets a billionaire Peter Parker who wears the Spider-Armor MK I.
The armor appears in Marvel Super Heroes vs. Street Fighter but as a secret character which is basically a palette swap, this version of Spider-Man that has limited armor, based on a metallic suit he wore in the comics as well as episodes later aired in the Marvel Studios animated series. He jumps sightly lower than before due to the heaviness of his armor.
The Spider-Armor appears in the game Spider-Man 2: Enter Electro with the same abilities as in the Spider-Man 2000 video game.
The Spider-Armor makes an appearance in Spider-Man: Web of Shadows as an alternate costume for red-and-blue Spider-Man after completing Act 2 in the Wii version.
The Spider-Man Armor is also a alternate costume for Miguel O'Hara in Spider-Man: Edge of Time if the player has a game save file of Spider-Man: Shattered Dimensions on the system.