So as the title says, when in first gear as I engage the car shakes really bad feels like the wheels are hopping, however it does not do it in other gears. Never had this problem before. However, when I rev it up to 2k rpm or so and let off it isn't as bad or sometimes won't even do it at all. I just got my supra back yesterday and other than the rebuilt engine, I had the shop install a Southbend stage 4 clutch, driftmotion lightweight flywheel, and a one piece shaftmasters aluminum driveshaft. I let the shop owner know and he said that my aluminum driveshaft is what's causing it. I've read up on reviews here regarding the shaftmasters driveshaft and none indicate that they have this issue, so I'm pretty sure it's something else, clutch maybe? Any input/help is very much appreciated.