MXA PRODUCT TEST: Pro Circuit RM-Z250 T-4 GP System Jan 15, 2009 INSIDE THE PRO CIRCUIT T-4 GP RM-Z250 PIPE WHAT IS IT? The Suzuki RM-Z250 (2007, 2008 and 2009) has a potent low-to-mid powerband. The Pro Circuit T-4 GP pipe makes it more of a mid-and-up engine. Read More...