The GT2540R is the newest in Garrett GT technology. The GT2540R, also known short as 25R, was the first and most popular of the GT series T25 based turbochargers to hit the US market and make big power. Horsepower as high as 397 whp has been achieved out of this turbocharger, using the stock intake manifold. Cars have run 380 whp on pump gas with this turbocharger with simple bolt on parts such as cams and an intake manifold. Full boost is around 4400rpm in 4th gear. A .64 A/R version is available, with 450rpm earlier spool up, please call when ordering the .64 A/R GT2540R. Normal online sales without calling will send a .86A/R GT2540R, specifically to make high top end power.