I recommend you download this mod. Gta IV peds to Gta Sa.

[D_Donnerfield]

Basically, these converts all/most of the peds on sa to the ones on IV.
I took an ss of the fat biker,

By sohailisawesome at 2011-08-06

So heres the link to the download.
http://www.madpenguinproductions.co.cc/2010/10/gta-iv-peds-to-sa-pack-v03-beta.html

[/b] Scroll down and download the NEW BUILD which is VO.3.[b]
Now, don't try to get ahead of yourself because you think you know it.
Follow these instructions to complete the installing proccess.
http://www.madpenguinproductions.co.cc/2011/01/gta-iv-peds-to-sa-pack-installation.html
Read everything carefully, and read ALL the instructions.
I recommend you download it, as it really good and the characters are of good quality and detail.

[b] REMEMBER: Always keep a backup!
UPDATE: One warning, SKIN 105, 106 and 107 Keep crashing on my PC after downloading this, so I decided to replace it with the Grove street Pack mod which is avaliable on the GSF Page.

[DeRon Ellis]

I only mod common skins. Most GTA IV skins don't fit in SA well. Like the biker for an example, his hands are going into his hips. Personally, I think the GTA IV EMS skins are the best skins you can use on SA,

[D_Donnerfield]

Fair enough, But have you tried it yet?..