Hi Eddie,
I have owned my 74 Commando Roadster since 1980. I bought a Harley in 1996, a Softail Custom FXSTC. This bike has the EVO motor, 80 ci, 1340 cc. Probably the best motor Harley ever made. The EVO is a 100k mile motor, I have 65k on mine with original pistons, 2nd set of rings and valve stem seals.
They made them from 1985 to 1999/2000, then they introduced the Twin Cam motor @ 88 ci. which is the base for which the 103ci motor you are inquiring about. In 2007 ?, they upped the CI to 96, now 103 CI, I don't remember when they did that, 3 years ago? Anyway as I stated, my bike is a Softail, which is a name they coined because the shocks are located under the chassis, so you don't see any shocks on the side. It kind of looks like an old hard tail. Now to answer your question in regards to suspension, Dyna VS Softail...I lowered my Softail 2" in the rear with a lowering kit, strictly for looks, and my preferred ride height. You can just roll a beer can under the frame at the lowest point. My ride isn't that great, but it looks "Cool".No, I don't go through the twisties trying to hang with a 412 lb. bike. Mine weighs 690 lbs. , my exhaust would be scraping on a right turn and I'd burn up my saddle bag on a left turn, but a 150 mile ride is no problem. Anyway I swore I would never buy another Softail again, my dislikes were that alternative shock selections are minimal and very pricey. Best bet for a Softail is an adjustable air ride system $1500, if you are lowering the bike. If you are keeping your bike with the stock ride height things are a lot better.
The Dyna has shocks on the side, easily changed, no special tools and you can get them in different lengths, gas, air, etc.. I have 12" Hagons on my Norton. The Dyna also has mid controls, compared to my Softail which has 3" extended forward controls. I think the ride is a bit nicer on a Dyna model and shock options are greater and less expensive. My Softail motor is also mounted directly to the frame as I believe Dyna's are rubber mounted. The ladies like the frame mount as opposed to the rubber mounted version....A little more vibration. As far as performance any stock Harley is a dog. The first thing I did to mine was replace the cam, carb, pipes, and ignition, so I had to spend another grand for parts. As my 80ci 1340cc sits now, on the dyno I'm at 80hp, and 82fp of torque. The stock 103ci/1690cc motor doesn't put out more than 64hp. Anyway, the reason I bought my Harley was it was not comfortable riding the woman on the back of the Norton. When we go on one bike, we take the Harley. Two bikes, she rides the Norton....She always says, "I'll whip the sh*t outta that Harley" when we're riding together, but I think she's just happy I let her ride the prized machine. Another reason I bought the Harley was when the "Old Lady" was on the back she always pushed me forward into the Café Racer position. If I was you I would buy a used EVO bike, my buddy just got a 1999 Fatboy with 11k miles for $5500, and it already had an aftermarket cam, Mikuni carb , pipes and some other upgrades. Aftermarket parts are abundant and inexpensive. You can also buy an aftermarket replacement motor for under $4000...127 ci 140hp/140fp torque
http://www.ultimaproducts.com . Eddie...pull the trigger, but look into buying an EVO and upgrading it, or just build one yourself....unless you have lots of loot. P.S. I just rediscovered my Norton as I rebuilt the whole bike, better than new...I haven't let the woman near it yet, I'm having too much fun.
Adios,
Johnny Z