The other variable that will loosen up and provide more low end torque is your torque converter. Since your trani has been changed so many times, it'* hard to know how loose it is. You could have an el cheapo standard unit in there that only has a stall of about 1800 rpm.

If you stand on the brake so the car does not move in drive and then step on the gas simultaneously, what rpm will the engine flash up to maximum before it won't rev any higher with the wheels not turning :?:

Any tag on the transmission to verify this? There were a few different numbers, including what were probably stock numbers that were etched into the bell housing with a blue marker

I've tried it, and in my zero to sixty vids its about the same. Goes to about 2 and a half grand. But I'm almost positive this 'bucking/missing/shuddering' feeling I'm getting is coming from the trans.

OK, it'* normal then at about 2400 rpm.

Not yet... I'm trying to figure out what is leaking on it so the leak doesn't eat at the new bushing. I know that'* causing a knocking sound when shifted into reverse and when you take foot off throttle while you're moving, then re-apply. Atleast I hope that what that clunk is. But I don't think it can cause the shudder... because this shudder is like if you hold a note in your voice, it sounds like you're going over a washboard road, and doesn't have a pattern anymore. Today I was practicing getting rid of my tires and I felt a loss in power (I often wonder if that'* KR, but that'd be impossible on a stock setup I'd think). It was about 5 grand going about 15 mph lol and it shot down to three and caught traction, bogged, then I felt the power come back and it took off.

EDIT: I have the dogbone, and the fluid is dripping red... so it'* either power steering fluid (located directly above), or trans fluid. Clueless where trans fluid would be coming from.

The KR is possible even on a stock car particularly if your beating on it....5K @ 15 mph means your tires are spinning wildly and when it catches traction it puts a huge load on the trani. Some have been known to frag from doing this.
Red fluid is likely trani fluid. It could be coming from a radiator cooling line or the connections. Very dangerous if it sprays onto a hot manifold.

I'm aware lol and I don't usually beat on my cars. But it seems since I've started driving this one hard... the shuddering has definitely gotten worse. Like I said, now it'* at the point where you can hear my voice shuddering from the vibration if I hold a straight note. Now that you can actually feel the shuddering, I think I will take it back to the dealer and say 'with new plugs/wires/tested coils/injector cleaner/seafoam... what'* causing the shuddering'? Only route to go really is the transmission at this point... because you can't really see it on the tach.

More low end? L36?

Hrmmm.....

I can think of how I'd fix that.

Topswap! M90 on your car would be sweet. And I doubt you would be complaining about lowend power...