Car weight?
I have seen guys get carried away with the whole weight issue on electric sedans for stock...I was even foolish enough to buy ceramic bearings for my car in effort to lighten the drivetrain...I does not make a real difference in the end it is consitency and the ability to make car carry corner speed...really more consitency than anything.
If you really are 1 full second a lap slower (this is an enternity on most tracks) and your are driving "a perfect line" the likely cause of slow lap times is the fact that your car scrubs corner speed or you do not have right gearing. I would spend the money on different tires, bodies, practive fees etc to try to get your car to handle better....I have never met anyone go faster with ti screws or other hopups.
Just for fyi...one of the local racers at my track is on a real budget and he does not buy the newest and greates batteries, engines or car parts most of his cars and engines are second hand (he uses 2000mah batteries in eletric sedan seriously) and yet he finish in the top 10 week in and week out out of classes of 50 racers...He's got a strong knowledge of setup and he rarely makes errors and practices alot on raceday.
I am not slamming you it just that I have seen so many people get carried away in equipment and it really is just practice and setup.
Jamie