[Jeff Lee]

Additional safety equipment or safety-enhancing equipment is
always permitted and the levels of safety equipment stated in
this Rulebook are minimum prescribed levels for a particular
type of competition and do not prohibit the individual racer
from using additional safety equipment. Participants are
encouraged to investigate the utility of additional safety
devices for your type of competition. In disputed cases,
whether an item of equipment is safety-enhancing or
performance-enhancing will be determined by NHRA in
NHRA’s sole and absolute discretion.

The problem with a big number of racers is they have never opened the rule book up and would rather jump on the internet for advice than make a decision on their own. If one were to read the rule above, you would understand what Mark Y. is suggesting is allowable. He is, however, taking a chance that one NHRA tech official may not agree with the safety modifications and could be subject to discipline. However, I'd bet there aint ONE tech official that would do so.
The bottom line: "safety" is bantered about as code word for "performance".