Well, not to belabor the point, and I'm not trying to be difficult, but....
When it comes to classing cars, IF the ITAC were to consider a weight drop on a car, it simply can NOT use one example. Things that are unknown include:
Your engine: Did you sort though hundreds of con rods from the factory to find the lightest one? Then match yours to the lightest found? Pistons and every other moving part? Are the transmission and rear gear adjusted, aligned and lubricated with the lowest drag in mind? How about the exhaust system? Off the shelf stuff or custom designed through days on the dyno? And the ECU tune...same thing, how much dyno time. Ports matched? How many heads were flowed to find the best one? Same for intakes. Running gear...is it light? And on and on. These are the things that the top guys do.
now, about the E36...is it legal? is it a 10/10ths build?
These are things that we have no way to really know...and it gets very tricky to start making conclusions. And the cars are just the tip of the iceberg. Then we have to factor in the drivers, the track, the weather conditions. Even when most of those things are knowns, results and lap times are often inconsistent, with no known explanation other than, "hmm, track was slow that day"..
Even if hp numbers are submitted, those need to be taken with a few grains of salt as well. Different dynos generate different numbers, even if the car is the same.
Simply put, if the numbers generated by the process match the weight listed, it would take a serious mountain of evidence to even open a discussion on a weight change.
Now, it the process spits out a number that does NOT match what's in the book, well that's a different story.
Finally, it's not JUST about horsepower and straight line speed. It is expected that some cars will get spanked at certain tracks, while others will reverse the tide at different tracks. And the way the car is built (weight and distribution) the suspension, the dampers, and the elusive setup all play a huge role. Taken individually, it seems that each of those things isn't the difference, but collectively, they add up. It is expected that to win cars have every nut and bolt adjusted and tweaked. And they are driven brilliantly.
Don't take this the wrong way.... I'm not trying to discourage you, or be a jerk, i just want to shed light on how the system works. if you feel the weight listed is wrong, prepare a case and ask the CRB to have the ITAC run the process on the car.