The new 4 series is a new look to BMW and a very stylish convertible. The BMW 4 Series Convertible replaces the old 3 Series Convertible in the BMW range. The car uses the body and interior of the 4 Series Coupe, but swaps its fixed roof for a three-piece folding metal roof which tucks away neatly into the boot. The BMW 4 Series Convertible is a fabulous looking machine roof up or down. Some cars with folding metal tops tend to have bulbous rear ends to accommodate the bulky roof mechanisms. But BMW has managed to engineer its way round this problem by using a three-piece design and complex folding mechanism.