Richie:
I used Long Machine and Tool Shifters and found them to more than adequate. See
http://www.gforcetransmissions.com/shifter_5_hn1000.asp
I hate to see you go through a $2,000 plus investment just because the present shifter may not be adjusted/setup propertly.
You have not indicated what your rear gear ratio is. Changing to a Tremec will make a diffference in your ratios!
Jim