In terms of performance you probably wouldn't notice the difference by changing your RSMs unless the rubber on the existing mounts are completely worn away...
The real benefit isn't better handling, but a stronger shock mount. The e36 sedan and coupe have issues where the rear shock mount actually tears out of the shock tower. This is supposed to eliminate that problem. The Ti has a setup similar to the e30 which isn't as prone to have this problem, but it could still happen if you are using old worn out shock mounts with hd/sport/race springs and shocks.