cheapest harmonic balancer(non autozone)

[Coupe50h]

I think my balancer is due for replacement, i am getting a vibration at a certain engine speed, i replaced u-joints ect....fixed for a while, now a different vibe i can feel through the shifter,

my clutch seems to be acting funny, but noticed it smelling like burned clutch at the track, today i found oil all around the belhousing, would oil contaminated clutch make it vibrate? im sure it would make it slip, therefore causing the burnt smell...

now to the original subject, my balancer is 1 yr old, got it from advance, i hear they dont last long in performance applications, is the summitt s.f.i the cheapest high performer? sorry so long.....thnx for any advice.

oh yea, motor mounts (rubber) are cracked, but the engine stays fairly stable when i rev it?