Complex sentence: Tsuchiya offers Shikiba another race, but declines, saying that he has already raced him on the track, and knows how it's like, and gives Kaoru the GT-R keys saying he will not give up on Kazuki's.
Split into simpler sentences: Tsuchiya offers Shikiba another race, but declines, saying that he has already raced him, and knows how it's like to race on the track. He then gives Kaoru the GT-R keys saying he will not give up on Kazuki's.