There are dozens if not hundreds of ways to make a car faster than spending nuts money on a ti exhaust. If you have a big bucks build on a super car or all out race car and allowed to save some weight with a ti exhaust it might make some sense but on a FiST it likely never would.
I say this as somebody that has been taking weight out of cars for 47+ years and made hundreds of threads and thousands of posts about it and built the lowest weight know full suspension mountain bike known in the world 15 years ago, 20.4lbs and built to race not just "scale queen" like some cars are "dyno queens"