Those plants look pretty streched what light are you using? and what ever it is get it closer! they look as if they might need a high nitrogen fertalizer, i recomend fish mix it gives alot of structure to the soil also and has lots of amino acids and vitaimins wich they thrive on, it fucking stinks but it's a bloody good fert.As for repoting i don't think is nesecery, i'm growing in the same size pots and mine are 3 times yhe size.