The generator matrix

 1  0  0  0  1  1  1  1  1 2a+2  0  1 2a  1  1  1  1  1  1 2a+2  1  1  1  1  1  1  1  1  1  1 2a  2  1  1  1  1  2  2  1 2a+2
 0  1  0  0 2a+2  0 2a+2  1 3a+2 2a 2a+2  3  1  3 3a+2 a+2 a+1  a 3a+1  1 2a+3 2a+1 3a+3  2 a+2 3a+2  0 a+2 2a+3  0  1  1 3a+2 2a+1 2a+1 2a+2  1  1 a+3  1
 0  0  1  0  2 2a+2  0 2a 2a  1  1 3a+3  1 3a+1 2a+1 3a+1 a+3 a+3  1  0 2a+1  a 3a+2  a a+2 a+3 3a+1 2a+2 3a+3 2a+1 3a+1 3a a+2 3a  2  a  0  3 3a  1
 0  0  0  1 2a+3 3a+2 3a+3 3a+1 a+1  1 3a+2  1 2a+3  a 2a+2  2 2a+1  1  a  1 3a+1 2a+3 a+3  3 a+1 3a+3 3a+3  1 a+1 2a+1 3a+3 a+1 2a 2a  1 3a+2  0 a+3 3a 3a+2

generates a code of length 40 over GR(16,4) who´s minimum homogenous weight is 108.

Homogenous weight enumerator: w(x)=1x^0+2520x^108+7719x^112+12300x^116+17208x^120+17088x^124+7869x^128+828x^132+3x^144

The gray image is a code over GF(4) with n=160, k=8 and d=108.
This code was found by Heurico 1.16 in 51 seconds.