Also, if someone would recommend another

Try looking at the Brainstorm Accelerator for the Plus.  I believe it is
the best solution because of the performance and price.  Why spend $800
upgrading a computer that is only worth $300 ????
  The brainstorm accelerator is around $225.  It speeds up the internal
clock speed to 16MHz.  That may not seem like much but it also speeds up
SCSI transfers.  I think that feature is unique to brainstorm.
Check it out.