GTti CB70/80s' engine was the fastest 1000cc cars in the world after compare it to detomaso hde 1.6 , starlet 4e-fte, nissan march superturbo n mini subaru. 3 cylinder, twin cam, twin cam gear, 76mm diameter of factory forge piston, n also have a balancer mode beside the crankshaft that only have in car for 2000cc turbo n above!. Street tuned 4 GTti without heavily change the internal can approxe 120-130whp in stage 1, 130-150whp in stage2, 150-180whp in stage 3 n finally 180-240whp in final stage. my pals from australia send me one of his frens spec after completely change the internal (forge piston n conrod, aftermarket balance crankshaft) with low boost (2bar in turbine gt25) approxe 360whp n high boost (2.7bar) 440whp.