My advise to all sledders if you are having darting problems most likely I believe 95 percentile its due to Suspension not tuned properly.
Consider all the advancement and technology put into late model stock skies and skegs.
Just saying I have logged over 80K miles in Quebec since 1990.
Tuned suspension in 14 new DOO s and one Yamaha Viper 2002 over that time resolved any darting issues.
Yes I did replace the steel skies in the mid 90 s with plastic aftermarket set. All years there after all stock skegs with 6" carbides instead of the 4" stock.
Correct when the pilot ski stock on my 2004 GSX was first introduced it was similar to the simmons, though I never purchased simmons have tried them on other sleds.
My experience with the pilots then had no ski pressure like the simmons.
Bergstrom Skegs I tried for Sh#ts and giggles. They are fun, but no necessary !