new trans shakes

hello, I'm new to this site and could use some help. I have a 95 cobra and have had to put a new tranny in. I went with a 3550 due to budget constraints. I have also just put in a tokicko suspension kit. I was finally able to take the car out and noticed a vibration in the shifter and seat of pants above 60. I'm wondering if there is some conflict between the lowering kit and the driveshaft spacer that came with the 3550 kit. Thanks

Thank you, you are right I did not mark it now that I think about.( i didn't have good instructions and kinda winged it) how big of a part does the 2* angle play into it thats what i was told by the place i got the 3550 from? thanks again