best iOs for iPhone 3g?

[iamamac]

I've got my hands on an iPhone 3G and it is currently running iOs 4.2 HORRIBLY.
I would like to use it as my second phone and as an occasional mobile browser as my iPod touch doesn't have 3G 🙁
I don't need multitasking or anything else (including jailbreak) but I want a fast iPhone. Obviously, it's not a 3GS or a 4 but I want it as fast as it can be so which version do you recommend? 2.2.1, 3.0, 3.1.3?
Nothing else matters but speed and responsiveness 😀 I'll jailbreak it if it'll improve the performance.
I'm eagerly waiting for your replies 😀

 

[celticpride678]

iOS 3.1.3 is probably the best.

 

[iamamac]

iOS 3.1.3 is probably the best.

Jailbroken? 😀

 

[celticpride678]

Jailbroken? 😀

More tweaks you install, the slower it will get.

 

[Applejuiced]

iOS 3.1.3 is probably the best.

Yes.
I wouldn't go any higher with a 3G.