SushiGuy-
Evo 3 is a great car, you don't really need anything newer and in stock the shaft is great for quickness.
If you really want to go fast you need the "good" brushes in the motor either 4499 or 4505 or 4503 or light speed, etc(and properly broke in). but beware it is harder on the comm and you will not be blazing fast for 9 runs as they will fall of after a few runs. If your club is very competitive you will have to cut your comm every 4 runs or so to win the A main.
With an off the shelf mass produced motor its somewhat hit or miss to get a fast motor. The fast motors are just as cheap as average motors from the hobby shop. An example you can buy the mass produced monster stock at my local hobby shop for $38 OR you can buy an Axiom, putnam, Kisbey, (all highly recommended) for about $40 at some hobby shops or more likely mail order.The work that the smaller motors tuners put into their motors is a great bargain and these motors will be faster than 98percent of the mass produced motors.
Batteries- sorry to say yours suck. Voltage is VERY important in stock. Look at the new IB3800's . You can buy 1.19's for $40 to 60. Look at some of the motor guys web sites (Brood I think and others on this board) that have batteries, they are never before seen bargains. 3300 and 3700 are so bad compared to what the IB voltages are now that many hobby shops can't even sell them.
Bearings- Metal shielded bearings are the cheapest bearings and very free of friction if kept clean. Just about as good as ceramic bearings when clean and lubed.
ESC- I have a KO vsf1 comp, I am not sure of the features in your ko esc.
ESC setting is very important. Make sure current limiter is off, max punch for stock. VERY IMPORTANT for stock racing. The ko staff answers questions on the vsf1 thread, ask questions there or call ko.
Gearing- Getting a gearing setting from somebody else is only the start. TRY going up a couple of teeth and down a couple of teeth(one at a time) and see if you hit the sweet spot on the motor where the motor is as fast as it can be. Different drivers will use different gearing for the same equipment. Gearing on a small tight track for a monster stock is fdr 7.0-7.2. I usually run 6.8 on my local tracks. Gearing is one thing that is trial; and error. Just to give you an example of how important the right gearing is- At a race I had the fastest truck by far with the right gearing, sooo fast that the otherdrivers were demoralized and lapped by my truck(T3). The next week I loaned my truck to somebody else as I could not attend the race. This other person went down 1 tooth to get more punch. Well the truck went to the back of the pack. I watched the 2nd qualifier and saw my truck at the back of the pack. I put the right pinion back on the truck for the main. The truck was back up to speed and setting a new track record. So moral of the story- The right gearing is key to having a fast A main winning car.
Good Luck