While I'll agree that a club shouldn't completely rule out having a mod class, tha fact is that stocks do make it easier to learn how to drive & set up a car, plus stocks are easier on drivetrain components, tires, etc. At my local track, we have a group of guys(including myself) who can & do run mod from time to time, but it's always very hard on the cars, ESPECIALLY tires(the surface is pretty abrasive). We can easily make a new set of tires all but useless for mod in one or 2 race days(though they can still be ok for stock). I don't know about you, but I can't afford to buy new sets of tires every other week(& many of the others here agree), so we also run stock quite a bit(& we have an Expert Stock class so the less experienced stock racers don't feel they HAVE to run with us, they only do if they want to). Now with stocks, a set of tires can actually last a LOT longer(here as many as 6-8 weeks if your car is well set up & you use the right compound), plus there are fewer problems with outdrives CVD's & diff parts wearing. One other thing, you CAN actually use good batteries for stock, if anything they help you more there, as everyone's available motor power is much closer to each other(so that little extra bit of voltage helps immensely). And as for GP3300's, they do actually work out better than 2000's or 2400's in a number of ways, most notably in that at the end of a 5 minute race, their voltage hasn't dropped off NEARLY as much as with 2000's or 2400'sso you can run laps every bit as fast at the end as you do at the beginning(the GP's only real drawback is weight, but if you've already worked on getting your car to just make minimum weight with the GP's, it's no real issue). And one other thing, running stock also makes it neccessary to learn to drive better, it's a matter of having ZERO mistakes & learning to maintain your car's momentum. There's really nothing at all wrong with stock, it's just different that's all. Maybe of you gave it a chance, you might come to appreciate it(& it might even make you a better driver in the process).....
