「なお、制動を行えば車両は当然減速する。」という一文を英訳するなら、

It should be noted here that a vehicle naturally decelerates in response to breaking operation.

よりも、

In this context it goes without saying that a vehicle decelerates in response to a braking operation.

の方がはるかに自然かつ正確です。

当然、Z社装着品での手配をよろしくお願いします。」という一文も同様で、

It goes without saying that we will need products prepared by Z-company, and I would much appreciate your cooperation.

が適訳です。