I had tryed the GPL mod too. I took a few days to try out the cars and get an idea about them. Thank you, Matteo, for have linked the mod and having thought of me.
I was quite strict with the prototypes mod and I must be too with this, in some things.
Graphic is really bad and far below the level of Kunos cars. Cockpits are truly awful (probably used parts of GPL-cockpits). In some cars I don't see the RPM instrument, it is covered. In this mod body animations are good instead.
Sounds are good and in some cars really good, just few and small problems with echo/doppler (in BRM for ex.) or obfuscated suffused at some RPM (really small in Cooper for ex.). In any case, the sounds are good and cool, as said before.
Physic seems really good, very good. Each cars have a different and detailed handling. The ffb (which often gives problems in the mods) here is great and the feeling is exceptional, I would say a job at the same level of AC.
Cars are fantastic to drive! As for the mod prototypes (but also for many AC cars of the same category, ex. DTM, etc. etc.), the cars are not balanced and have different lap times (not as much as I though). This is realistic.
This is realistic but makes it difficult to do championships in AC. AC-players are used to racing all with the same car, even small differences on the lap can create controversy, usually. Here is the success of the TCR mod.
I did several laps on Ceolmor's server and in fact some random players were concerned that the cars were not balanced.
I think, have cars slower and some faster is not a problem; there are several solutions for this, often already experienced in the past:
-a season using more cars, old GPL way, ect etc.
-give the faster cars to the usually slower players, and the slow cars to the fast players.
-random car for pilots
-etc etc.
I think the third option is the most interesting. If a pilot has assigned a BRM, his goal will be to aim for some podium during the season and finish the championship in the middle of the standings. Who will have the Lotus, will simply have to try to dominate.
I understand, however, that probably for who find no stimulant racing for positions out of the points (and so want points for all), will not like this option.
For a completely even championship, just take a car and use different skins.
PS: on the "install and notes" file there is a list of tracks for do the '67 season, and they are the same that we thought.