What harts did you look at? I can only find one Racing Hart CPF and its 15x6.5, i looked at the other forged (CP series) ones, 18x8 is 8.2kg, same as the te37 18x8, 8.2kg?
Strange, TE37s are 18x8 8.2kg and the CE28s are 6.7kg 18x8...
Whatever the case, jap wheels > tempe wheels lol.
Will let you know if sale falls through.