Mishimoto 01-07 Subaru WRX and STi Manual Aluminum RadiatorWhether you daily drive a stock STI or rallycross a modified WRX, an efficient cooling system is key to extending the life of your flat four. The plastic end tanks of the stock radiator are especially prone to cracking from years of constant variation in temperature. A radiator failure can result in overheating, head gasket failure, and other engine damage that can quickly put an end to a fun day at the track. Protect your investment with the