Lowering SR has a bigger chance of pitting you against drivers closer to your skill level.
Most drivers are in SR.C and SR.B which gives matchmaking a much bigger pool of DR to match you with.
In SR.S you are usually just grid filler for the fast guys.
I would personally get rid of the trophies. They only cause trouble, making people game the system to get easier wins etc, making them more aggressive to get the wins or cheat to get the fastest lap. (For some reason shortcuts still give you the fastest lap. If you want the fastest lap on Sarthe, simply skip the final chicane and ignore the penalty...)
Instead have trophies for total number of clean races and one for consecutive clean races (which is only an achievement in the game atm) as well as a trophy for staying in SR.S for x number of days. More fun trophies for close finishes, lapping like clockwork, staying close with other cars without touching for multiple laps.
Argh a new bug
Just as I get matched with Sturk the game hangs on this screen
@sturk0167 Did you see me enter the room?