They are great if you are going to replace the guides and I would suggest swapping to a 2.12 on the intake stock seat will use that and it would lower cost of work. Stock ex valve is usable if in good shape. That basic set up works extremely well. Going to a larger EX valve is an option however most builds will not show any gains that will be seat of the pants power you can feel.
You do see a lot of burnt up exhaust valves and guides.
I have seen 3+ sets where there are chunks of the guide missing....think the end of your pinky finger missing from the guide and these were from running motorcycles.
100% agree with installing a larger intake valve 2.12-2.13 range works well,using the stock diameter 2.08 intake it is possible to get the flow numbers up but because the throat is too large for the valve you don't see a increase in power output like you should.
Depending on the budget I also do not see a reason not to install a larger diameter exhaust valve,up to a 1.65 diameter will work well and you can get a much better profile on the seat....a little larger throat diameter and a pretty decent increase in airflow for very little money.