R1 Suspension Alternatives
If you are a 'big' boy (over 220#s wet), it is likely that you have found the suspension on both the FZ1 and FZ8 a bit on the soft side. Furthermore, the shock action is lacking over dips and bumpy curves.
First, the rear. The FZ1 (GEN II) and FZ8 shocks have identical mounting dimensions. The FZ8 spring rate is 448 lbs/in. The '06 FZ1 is 685 lbs/in and '07/later 650 lbs/in. Thus, the swap out to FZ1 adds significant springing to the FZ8. Unfortunately, it does not significantly improve shock absorption.
R1 shocks ('04-'08) have the same mounting eye diameters and width, but are shorter in eye-to-eye length - thus the need for an adapter. The adapter requires a bit of modification to the FZ8 Voltage Regulator tray but not beyond the skills of someone with a vise, hacksaw and drill. The adapter does not fit on bikes equipped with ABS.
The '04-''06 R1 shock has both compression and rebound damping adjustment with a spring rate of 476 lbs/in. The '07-'08 has an additional high-speed compression adjustment with a slightly heavier spring - 531 lbs/in. Both series shocks have alloy bodies and are superior to the stock FZ.
Generally speaking, if you are less than 180 lbs wet (and you don't 2-up or have a bagger), you need a spring rate somewhere in the 450-500 range. Under 220 lbs you should have 500-580 lbs/in. Over 220, you require 600-700 lbs/in. Luckily, there are several manufacturers of accessory springs (i.e.:Racetech ~ $120) for the R1 shock. So 'big boys' have to pay a bit more to carry the weight.
The front end is a similar problem. Stock FZ8 is 50 lbs/in. Unfortunately, neither the FZ1 or R1 springs are a swap, varying from 53 lbs/in (FZ1) to 50-51 for the R1. Although the mounting dimensions of both the FZ1/8 and R1 tubes are similar, the R1 tubes are shorter. Fortunately, the '07-'08 R1 is only about 7mm shorter.
From experience, the best method is to swap a complete '07-'08 R1 front end, including the triple clamps. That gives the benefit of 6-pot radial brakes and a slightly lower profile upper triple clamp to make up about 4mm of height difference. Unfortunately, a significant amount of modification is required to accommodate new handlebar mounts and lower triple swing stops (search the FZ1oa forum). Swapping just the tubes requires the R1 front axle, spacers and wider rotors (R1 +.5mm). Because the R1 trail is different, you cannot mix the upper & lower triples. It is a lot easier/less expensive to use a R1 front wheel assembly. If you are in the 'big boy' category, stronger R1 springs will be required.
Cost wise, the R1 front end will not likely be inexpensive. There may be a market for the take-off parts to offset the cost to a few hundred dollars. Consideration should include a 'simple' spring and shock cartridge upgrade if you are not mechanically adept.