Yanno I could be wrong but I swear that looks like plywood and not MDF.
MDF (which is in the particle board category) works best because it is most dense. Wood would last just as long it simply produces more noise and a cabinet\enclosure should not produce noise.
Some of the best enclosures I have seen where made from either 1" thick MDF or concrete.
The concrete ones were not in a car...... I wouldn't recommend it.