Testing to evaluate performance needs to be done, but the challenge is that a good performance test can potentially identify serious issues that can take considerable effort to fix. So the concepts of performance testing(engineering) need to be in the forefront and applied at the early stages to engineer in performance.

Note that the concepts of performance testing, tooling and process are not therefore applied at an earlier stage but done at the early stages of design and early construction and integration. The potential advantages may be: lower cost of performance tooling, lower cost of fixes, smaller tooling rather than a big-bang costly tools.