An instrumented shell for sensing drilling parameters of a drilling assembly positionable at a wellsite. The drilling assembly includes a top drive assembly and a downhole tool. The instrumented shell includes a shell body, instruments and an interconnector. The shell body is positionable about the top drive assembly, and has pockets extending therein and a cover positionable about the shell body. The instruments include sensors, and are removably disposable in the pocket and sealable therein with the at least one cover. The interconnector includes a top drive connector removably connectable to the top drive assembly and a shell connector removably connectable to the shell body with a cable therebetween to pass signals therebetween whereby drilling parameters of the downhole tool may be directly collected.