THE ITR IS 600LBS LIGHTER HAS 8500RPM REV VS.8,000RPM GSR. NO SUNROOF ON ITR'S TO REDUCE CHASSIE FLEX NO CRUISE CONTROLL. THE TRANSMISSION IS GEARED ALOT SHORTER TO KEEP THE REVS UP WHERE THE POWER IS. ALSO THE ITR HAS AN LSD TRANS SO BOTH WHEELS PULL EVENLY TO THE GSR'S ONE WHEEL SPIN. THE BRAKES ARE HUGE ON AN ITR. GSR'S ARENT MUCH BIGGER THAN A CIVIC DX. ALSO ITR'S HAVE LARGER CONTROLL ARMS AND 5 LUG INSTEAD OF 4 LUG. THERE IS A HUGE BRACE UNDER BACKSEAT THAT ACTS LIKE A ROLL BAR. PLUS F/R UPPER STRUT BRACES AND A REAR BODY PANEL BRACE AND MUCH LARGER SWAY BARS AND REINFORCEMENTS. THE R WILL SMOKE THE GSR IN ACCELERATING,CORNERING, BRAKING AND LEAVE YOU BREATHLESS WITH ITS NEAR PERFECT BALANCE