If your shop is in the business of selling performance, especially to street and/or moderately budget-constrained clientele, then some of the best free advertising you can get is by word of mouth from satisfied customers. Often this can be no further away than taking advantage of a few simple machining operations and explaining to your customer the potential gains versus the cost.
Your head/block surfacing equipment is a good example of machinery that performs a simple operation that can significantly contribute to an engine