The Sandaime Kazekage had his unique ability to manipulate metal dust and magnets. Garaa has the ability to Manipulate sand with the help of Shikaku. From what i see, it would be a close figt, you have on the one hand arguably greatest KazeKage v Godaime Kaze. Both have similar abilities that are extremely destructive. Garaa appears to have a slightly weakness at close range due to his inability to use Taijutsu, instead, relying on sand manipulation. It appears Sandaime was however proficient at other Jutsus and only later developed Kotesu. It looks as if a battle between the two would be fairly close..
Considered the Greatest Kazekage (of course this was before Garaa was Kazekage, in fact he wasn't even born).
His abilities are similar to the abilities granted to Garaa by the Shikaku. In fact it was from seeing the Shikaku's ability to manipulate sand with his chakra that Sandaime decided he could do something identical with sand.
He developed of a special technique called Kotetsu, manipulating metal into weapons. It is known as the deadliest technique in Sunagakure.
Sandaime's Databook stats/unknown
Garaa's ability to manipulate sand is extremly verseatile and forms basis of many Jutsu. He can alter his sand's properties to make it as hard as metal forming a perfect protective barrier aound him. The sand can be used for short and long range attacks, his most destructive being Desert funeral, 'Sabuku taiso no jutsu'.
I'll post them later