As a lifelong Mustang collector, I see this problem a lot. The issue is that many,
many sites do not give extra value for a Saleen package, regardless if it is an
S281, S281 SC, etc. Banks also do not lend any money above GT value on a
Saleen as they count Saleen as an aftermarket package and thus it does not add
additional value. Roush is the same way. It is extremely hard to sell a Saleen or
Roush for anywhere near what you think it is worth as you will need a cash buyer
who values the car the same. Your cash buyers know the struggle you are having
with getting the value you want and will likely lowball you to death. I've been in
your shoes many, many times and it is very frustrating. However, the short answer
to your question is that there is no option for a Saleen convertible when listing and
you'll only get GT value on the car, which is how a dealership will appraise it as
well.