If I remember correctly adding the 74mm TB gave a gain of 7 hp. Contact Eurocharged Performance, clint@eurocharged.com or jerry@eurocharged.com. I went to their shop and we dyno'd each upgrade. changing from stock filters to K&Ns, 74mm TB, 74mm MAF, along with the Eurocharged Tune of the computer. Mine was at stock ,I think 179RWHP before and after all mods, including 2.75 inch air intake tubes ,211.4 RWHP. Pretty good gain for less than $500.