yes sp1 exhaust are hard to come by, they wont fit sp2 headers.
You can fit SP2 headers on a SP1 which will greatly open up your options, this seems to be the most popular option.
"Most" of the sp2 full systems will fit sp1 but there are some caveats and they are not cheap.
if you decide you want a set of SP2 headers to fit on your SP1, i have a set for sale, $250. im in atlanta.
2003 SP2: Everything I could find.
1991 Honda HawkGT
Dec. 2011&2013, Sep. 2015, May 2019 BOTM