2009 INFINITI M Power Train Problems

I RECENTLY BOUGHT A 2009 INFINITI M35. MY VEHICLE AND PROBABLY MANY OTHER 2009 INFINITIS WITH THE 7-SPEED TRANSMISSION HAS THE FOLLOWING ISSUES: 1) HARSH DOWNSHIFTS: THE VEHICLE SUDDENLY DOWNSHIFTS AND THIS ACTION BRAKES THE VEHICLE SIGNIFICANTLY WITHOUT THE DRIVER'S WILL. IF THERE IS ANOTHER VEHICLE FOLLOWING CLOSELY IT MIGHT CRASH THE INFINITI FROM BEHIND. 2) LAG OF POWER: SOMETIMES THE CAR IS "SEARCHING" FOR THE RIGHT GEAR, RESULTING IN A LAG OF POWER. THIS IS VERY DANGEROUS ESPECIALLY WHILE MERGING INTO HIGHWAYS SINCE THE CAR SOMETIMES DELAYS/REFUSES TO ACCELERATE. 3) DOWNSHIFTS AT WRONG TIME: I WILL DESCRIBE THIS ISSUE USING AN EXAMPLE. ASSUME YOU MAKE A FULL STOP AT A STOP SIGN. THE CAR STILL HAS 2ND OR 3RD GEAR EVEN IF THE CAR HAS STOPPED COMPLETELY. WHEN YOU BEGIN ACCELERATING THE CAR DOWNSHIFTS TO 1ST GEAR, WHICH PUSHES THE CAR FORWARD IN A VERY HARSH WAY. VERY DANGEROUS...