same here... more collecting and testdriving and adding notes and skins , rather then actually enjoying the many of marvels I have already in my collection (6817 cars now). Still every day I can't help but look to see if there is yet another new mod...
But I guess that's also the big part of AC , collecting and hoarding...
What I do is , I make sure to have the correct tags on each mod, and I rate the cars in CM , and then in CM content I work with filters instead of deleting the lesser ones. Else when you are in a server, you might miss a car and not be able to join the server because you do not have it locally.
Also when you do have all the cars on the server, you can see how many stars you gave each , so you can choose the car which has your best score...
And you can downsize the results to pick from (for a offline quickrace for example ) by using filters,
eg. rate:5 & tag:'rally'
will yield for me only the mods with tag rally, which I gave 5 stars (bringing it down from 240 cars with the Rally tag to only 40 cars to choose from ...)
rate:5 & fav+ & tag:F1 -> only 42 cars to choose from (out of 484 F1 cars in my entire collection),
and you can also add year filtering , for example:
rate:5 & fav+ & tag:F1 & y<2010 & y>2000 -> will only let me choose from 7 cars
You will need to put time in adding the score, tags you want to use, and make sure that the Year parameter is always filled in...