I know this thread is about a month old, but I have done both Corbin and Sargent on my '01 Mille. The used Corbin I picked up was actually for the early '98-'00.5 Mille's so although it fit, it left about an inch gap between the front of the seat and the tank. I didn't weigh anything, but the Corbin was significantly heavier than stock. The foam was also much firmer. I made a 10 hour ride with this seat and my butt didn't kill me, so it was a worthwhile mod in that respect. Leather quality is pretty nice, but the base pan construction looked kinda like a high school shop class project. I mean, it worked and fit with a little persuasion, it just didn't look very professional.
I sold it and picked up a used Sargent seat for '01+ Mille's. Now we're talking! Much less weight than Corbin and only slightly heavier than stock. Firmer foam than stock, but more giving than the Corbin. Wider seat area gives me more room to move around and change my sitting position - very comfortable. Construction is very professional looking and fits flush with the tank and slides on and off my quick release pins easier.
The only thing I like better about the stock seat is the surface material is grippier. I think that will work better on track when hanging off through the corners.
Biggest difference is the firmness of the foam in each seat. My research has shown me cushier seats allows more blood to pool in areas on your bum and less air flow to dry up sweat. That results in the monkey butt that much quicker on distance rides where you sit in the same position for extended periods of time. Firmer seats address that, but the question to the rider is "how firm is too firm?"
After riding with all three seats I'd have to recommend the Sargent hands down. I'll be putting the stocker on for trackdays. If I didn't need the cash to buy another seat the Corbin would have made a baller barstool seat.
