Gasoline direct injection (GDI) is not quite ready for prime time technology. Severe issues include high pressure fuel pump failure, gasoline diluted oil, carbon build up on intake valves and excessive noise.
Let adventurous early adopters with deep pockets take the hit for the team. Prudent individuals wait for new technology to mature and prices to moderate. Less costly, lower tech cars markedly reduce exposure to dissatisfaction, expensive repairs and replacements.
Lexus' design of the D4S dual injection system (using both port and direct injection) is a proven design since 2006. It has worked flawlessly and doesn't suffer from any of the negatives of some of the direct inject engines of the competitors.
"As described in the January 2006 issue of SAE Automotive Engineering International, the system primarily relies on the port injection system when low engine speeds are combined with high loadings. Under these conditions, a direct injection scheme cannot properly atomize the fuel, and so approximately 60% of the fuel is provided by the port injector. As engine speed increases, the direct injection system takes over more of the fueling responsibility, until eventually it provides 100% of the necessary go-juice. Obviously, there some complex calculations going on to determine the optimum fueling over the engine's operating range, and that has led to over 300 patents being issued to Toyota concerning the design of this system.
There's a 7% increase in HP and 7.5% increase in torque from the system, some of which comes from the 11.8:1 compression ratio that's enabled by the use of direct injection. Better yet, the benefits apply to the entire powerband, so this is a feature that will be useful to most any driver.
The dual injection system also reduces cold-start emissions. The port injection system dumps a bit of fuel on the back of the closed intake valve; when that valve opens, the fuel is evenly distributed throughout the cylinder. As the piston approaches the top of its travel, the direct system injects a bit more fuel into the cavity on top of the piston. The total air/fuel mixture in the combustion chamber is slightly lean, but the mixture is significantly richer in the area around the spark plug, making it easier to ignite in a cold engine. The result is quicker warm-up and smoother operation when cold."
You can see cut-aways of where the injectors are in the engine. One in the intake runner (port) the other in the cylinder (direct injection)