Which do you need, a cordless drill or impact driver? Of course you need both, at least I do. If you've never tried an impact driver take the time to do so, and time to stand in the checkout line once you decide to buy it.
Einhell 4513692 18 V TE-CD 18 Li Solo Power X-Change Lithium Ion Cordless Impact Drill - Red No description (Barcode EAN = 4006825593327). http://www.comparestoreprices.co.uk/latest2/einhell-4513692-18-v-te-cd-18-li-solo-power-x-change-lithium-ion-cordless-impact-drill--red.asp