I bought an aftermarket valvebody I bought off of eBay from a speedshop in California and had a local transmission shop install it and went with full synthetic trans fluid and it tighten up the shifts a bit. I just tried to contact them and found out they are no longer in business. I don't know if there is any transmission kits for the '11 and newer Sonatas. I will look into it this weekend. If I find anything I will send you a link.