The Eternal Rivals vs. The Sand Siblings.

[Unbiased]

Kakashi and guy hands down. Guy can take temari and kankouro very quickly if he goes 6th gate, and if he needs too, can go 7th and completely wreck them. Kakashi has great ninjutsu prowess and can hold off gaaras sand till guy finishes them off. You guys are forgetting, the manga refers to them as "the masters".

 

[Icelerate]

gaara handles kakashi,temari summons katamari and chops guy to peices, kankuro goes to bed.

I don't think Temari can do that to someone as fast as Gai.

OT: The Eternal Rivals win with mid-high difficulty depending on the range.

 

[Guardian of the Rain]

WOW, there's nothing to debate here. Kakashi and Guy owns easy-mid dif:sy:
Although, Gaara and the Sasori puppet will be nuisances

 

[Icelerate]

Sasori's poison will screw over guy. paralyzing his body and hindering his speed. Gai;s only hope is too dispose of the elder siblings quickly and not let the fight drag on.

Thats assuming that Kakashi can keep Gaara busy enough, but Gaara can sheild an entire village while fighting an S-rank opponent, he is an excellent multitasker

If Gaara can protect his siblings and still take on either Kakashi or Gai, while Kankuro defends Temari from a blitz using his puppets effectively, then the Siblings have a small chance and could take the fight to high difficulty.

WOW, there's nothing to debate here. Kakashi and Guy owns easy-mid dif:sy:
Although, Gaara and the Sasori puppet will be nuisances

How so? Gaara is stronger than either Kakashi or Gai.