Tricky Woo,
Aircraft with delta shaped wings do have higher V speeds, Boeing will have to overcome this with leading and trailing edge devices.
Engine inlet design is a bit of a black art, but the main idea is to present the airflow in a predictable and uniform manor to the engine at subsonic speed. It is necessary to slow the airflow down going into a turbofan/turbojet engine so that the flame stays in the combustion chamber.
The cone of the SR-71 engine intake sets up a shockwave at the right location and presents the engine with downstream axial flow in a controlled direction and subsonic airspeed.
The shockwave that is deliberately induced forms what is known as a choked nozzle and delivers a set about of air mass in a consistent direction through the shockwave regardless what supersonic airspeed the airframe is doing.
