PICS. Leafs curling+risk of rootbound?

Hi guys i have these 4 plants under a 400w HPS/MH (I dont know).

Their about 3 weeks into flowering and the roots are coming out the of the 3litre pots.

Will my plants have bad effects if i leave them in the small pots and should i definitely repot them or can i leave them in these?

Also the top leaves of the back right plant is curling upwards considering it is only this plant (the tallest) that is doing it and its only at the top i presume its the heat and how the close the light is, can any1 confirm this? Thanks

PS. How can u tell what bulb u have, MH/HPS? Ive lost the packet.

looks like your using HPS, the leaves curling can mean any number of things, from my experience the leaves curl up when the pores under the leaves are open wide to let off water to cool them down or when they are going through stress because of too much/too little/wrong nutrients. whats your ambient temp and relative humidity? They seem to be happiest from 73-77* F and 45-60% humidity.

I dont know right now because my hygrometer has broken, but as soon as i pick up another ill let you know