The "Lion-Hearted Letter Car" was becoming more and more a luxury ride, less and less sporty. Chrysler had other things on its mind, notably a move toward compact lines, and the need for a model competitive with the T-Bird. These were more urgent matters than performance on the track.
You can see this trend in the grille (in two parts, one black, the other red), in a rear bumper thick with chrome, and in a more comfortable interior, equipped with the new "swivel" seats. There was no more need to offer a dozen rear-axle ratios – two were enough. No longer did the buyer get a choice of engine; instead he was offered rear air suspension !

Nonetheless, the Letter Car still yielded impressive performance. A Motor Trend writer even maintained that the 300E was faster than the D, citing a time lower by 1.4 seconds for 0 to 60 mph. In that case, why was the E slower than the D at Daytona (120.5 mph average), outrun by 3 Chevys, 2 Pontiacs and a Corvette? Sports Car Illustrated tried the 300E with the following results: 0 to 60 mph in 8.3 seconds, 0 to 100 mph in 22.5 seconds, and the quarter mile in 17.2 seconds, reaching a top speed of 92 mph.

To sum up, the purchaser of a 300E got a versatile, fast and luxurious car, good in handling, and comfortable. Yet customers didn’t throng to the showroom. Between December 1958 and ’59 only 690 E’s were sold.