problem with control arm bushing and 5 spd swap

[Sonic Motor]

my 91 S13 is starting to make constant squeek in the front lower control arm while driving. I was told that it was my bushing. I have 199k miles on my chasiss. Now, would this have anything to do with my car trying to self steer while driving above 70mph? Cuz i have another 240 that also had teh sound and self steers at high speeds.

2nd problem, ive gotten a 5 speed swap on my vert, and almost everytime i step on the clutch, the RPM will drop nearly to 0. It has killed my engine a few times. Can anyone tell me what might be the problem?

Thanks!