When I first got my Bullitt back in 2009, the first thing I did was replace a leaking pair of Tokicos on the rear axle. In less than a year and maybe 500 miles later, one of the replacements was leaking again.
At that time, everything Tokico was removed and replaced with Bilstein.
Based on my experience with Tokico, I would not waste my money replacing a factory Tokico shock with another factory shock.
YMMV and I am sure others have had better luck with other than stock Tokico products!
One other thing to consider is that shock absorbers are only part of the suspension system. While the stock Bullitt suspension is stiffer than a stock GT, tires play a big role in suspension feel. Going plus one on tire sizing decreases the sidewall height which will increase the firmness of your ride. Tire type will also come into play. On 3250, I am running 18 inch wheels and summer only performance tires. Add these along with my Bilstein shocks and I know the ride will be firmer. I also find that as I get some heat into my tires, the ride smooths out but it is definitely not the smooth ride of a Lincoln!
Good luck with you decision!