Hey there, I'll post up because I've been plowing for about 10 years now.
First off - Dealers/plow dealers will tell you what they have to tell you due to liability and GVWR of the vehicles. The plow you are looking at is basically the heaviest plow made (with exception of the Blizzard 8610LP), coming in at around 1000 lbs.
The HEMI weighs a good deal less so it can accept heavier plows and stay under the GVWR for the front axle.
Regardless, yes your truck will hold the plow fine. My buddy/plowing partner has a Fisher XLS (Fisher's version of the Wideout, they are all owned by the same company) on his 02Ext Cab Long Bed Chevy 2500HD which is only rated for a 7'6" straight blade. He's had to do some work to handle the weight but he's been holding it fine for 3 years now.
As for the other parts - You can look into Timbrens which are basically large rubber bump stops that don't affect your ride. A lot of guys I know buy SuperCoils and they say the ride is actually better than stock. Another option is just buying 2" spacers. These all won't help save your suspension at all, they'll just keep the plow higher off the ground while driving.
Lastly - Ball Joints, Wheel bearings/hubs will go much sooner. A good aftermarket ball joint will last longer but the wheel bearings suck on these trucks and go pretty quick. IF you want to do this and have less repairs and save money in the long run, I'd invest in some Carli ball joints, and possibly a free spin hub kit. You'll be into it for about $2500 but you'll save gas with the free spin kit and not have to replace your hubs/ball joints again.
Good luck, there is a lot of money to be made when the snow flies!
BMW X5 & Chevy 2500 HD POS
2002 Ford F350 Crew Cab Diesel
1999 Dodge Ram 2500 Quad Cab 4x4 Sport V10
1998.5 Dodge Ram 2500 Quad Cab 4x4 24V Cummins
2004 Dodge Ram 2500 Quad Cab 4x4 HEMI
2003 Dodge Dakota Quad Cab 4x4 4.7
2002 Dodge Ram 1500 Quad Cab 4x4 4.7
2001 Dodge Ram 1500 Quad Cab 4x4 5.9 V8
1999 Dodge Ram 2500 Quad Cab 4x4 5.9 V8
1997 Dodge Ram 1500 RegCab ShortBed Sport 5.9 V8
Past -92 Daytona R/T, 94 3000GT, 91 TransAm, 88 RX7 TII, 89 YJ, 92 Bronco, 88 YJ, 94 F150, 96 Rodeo, 88,89,90,91 5.0 Mustang's, 03 Mustang GT, 04 SRT4