Thank you very much for your tips and replies.
I agree with most of you that upgrading to a costly glass panel is not worth if you are not flying IFR very often.
First thing I am suggesting is to check the 430 connection to the HSI. About the XPDR, C mode should be ok for flying in Spain. Overall in Europe, mode C and mode S will coexist for a couple of years.
8.33 reqs are ok with the 430.
About the GAMI injectors and JPI Engine Monitor I fully agree with you but with the current flight hours a year, it’s an important investment that would take years to cover.
Vacuum ADI and Gyro are old but still good enough if you are flying with iPad or similar for enhanced SA and nav b/up. At the end of the day, these a/c are not really IMC a/c and unless you are flying at night or through “soft” clouds, I don’t see myself flying in bad wx.