The Curt # C11372 is the only custom hitch available for your 2008 Lexus GS 350. A Class I hitch with a 1-1/4" receiver is often the only option for cars like yours since they don't have a high towing/tongue weight capacity.
It is possible that your bike rack can have the shank replaced if one is available. Some models have a 2" version and 1-1/4" version that can be interchanged. If you have the # SH22G you were looking at you could contact Kuat and ask for the 016-007. This would allow... view full answer...