I have got the lowering springs for my rover coupe but haven`t got the shocks would it do any damage to just put the springs on and not the shocks. There gmax springs 40mm thanks

It will shorten the life of the shocks and the ride will not be as good.

Also only fit the GMax springs if it is a 1.6 or 1.8 Coupe. They are not suitable for the 2.0 engine.

get the dampers as well mate, if you want it to handle propley, the original dampers were never made to be able to drop an inch + and im sure it voids the warranty on the springs as well

Dont worry about it being a 2.0 engine. People have lowered on Gmax springs before. All that happens is that the car sits a little lower at the front. The car looks and handles fine. Gmax stuff is just a bit harsh riding, but its no worse than any of the other cheap brands.
You can use the original dampers, but they are bound to be past their best by now and the car might feel under damped and they will wear out faster. It wont void the spring warranty as Gmax themselves say you can use the springs with OE dampers.