While taking at exhibitions, it is always better to have a lower depth of field.
A clear background will tend to distract your main subject.
I suggest trying a wider appreture and a wider lens. The second picture will look better if it shows more of the body of the jag, about 30 degrees more to the left and taken at same level or slightly lower than the window.
If possible try to go without flash.
For the elise, it will look nicer if taken from about 1.5 to 1.7m angle. The special "thing" about elise is the curve of the 2 scopes on the front bonnet.
Exposure is correct and colours are vibrant. Good attempt.