2016 MAZDA MX-5 Vehicle Speed Control Problems

I OWN THE 2016 MX-5 ND GT WITH MANUAL TRANSMISSION AND IT HAS ABOUT 35,000 ISH MILES ON IT, BUT IT'S STARTING TO HAVE TRANSMISSION AND GEAR SHIFT PROBLEMS. 1) THE CAR HAS ISSUES WITH ACCELERATION DELAY FROM GEAR 1 & 2, THE TORQUE, HP, NONE OF IT FEEL THE SAME AS WHEN I BOUGHT IT. 2) THE CAR WILL START HAVING RATTLING NOISE ISSUES COMING FROM UNDER THE HOOD, I SUSPECT FROM THE HEAT SHIELD WHICH IS MADE FROM THIN ALUMINUM MATERIAL. ALSO RATTLING FROM INSIDE, ALL THE PLASTIC PARTS FROM WITHIN THE CABIN, SEAT, DASHBOARD, ETC 3) THE GEAR BOX IS NOT SMOOTH AND SOMETIMES WOULD HAVE HARD TIME SHIFTING. IN MY CASE, I HAVE ISSUES FROM 5 TO 6. I LITERALLY HAVE TO GIVE IT 1 OR 2 SEC DELAY AFTER SHIFTING HALF WAY SO THAT IT WILL EASE ITSELF IN. ALSO SHIFTING FROM 1ST TO 2ND...