IO540, the +6g rating relates to normal flying conditions. Modern aircraft have very good impact ratings. The Diamond DA40 offers protection to 1000g acceleration, as I believe does the DA42.
The Grob is a relatively modern aircraft.
As with everything in aviation, it is a trade off. It's easy to add extra protection to a car, where weight affects only acceleration and fuel efficiency. With an aircraft, every extra kilo of weight added profoundly affects the flying characteristics. This is why aviation is usually at the cutting edge of materials technology. Modern aircraft materials are so far removed from what was in use 20 years ago as to be a completely different beast.
So yes, I would say that modern aircraft are FAR safer than those made a few years ago.
Of course, due to the high cost of buying and maintaining an aircraft, in comparison to that of a car, aircraft will tend to remain in service for longer. Of course, with an aircraft, very sensibly, most of the effort goes into ensuring that the accident doesn't happen in the first place, as a light aircraft accident, no matter what protection you have, is unlikely to be survivable. Therefore all the design and statutory effort goes towards preventing crashes in the first place, by having very high standards of maintenance, and by providing thorough training and regular assessment of the pilots.
It is unfortunate that we have experienced several fatal general aviation accidents in the past few months, but the numbers are still incredibly low on comparison to the number of flights, and flight hours, and anything else you choose to look at.