I have used Pinnacle leather cleaner followed by Pinnacle leather conditioner for 10+ years on my '90 Z TT with excellent results. The leather has maintained its original color and softness (except for one coarse region on the passenger seat) with no cracking. This car is my DD with 80K miles on it, so it has seen adverse conditions as well. Just apply several coats (initially) with your hand and let them sit for several hours before buffing. This might help restore the softness somewhat, and will definitely prevent any further deterioration.