I'm sure there are better shocks out there, if you want to drop some money into it. They're kind of an off size for moped shocks, so you'll probly have to poke around a bit. You'll want to beef up the subframe/swingarm probly. I welded 11ga cut to fit into the RH side of mine.
The Grande low end turned out to be jetting, though I have no idea how. I had it at 78 after kitting and everything was great, then after about 1000mi it (rather suddenly) started sucking ass on take off. Went over so much crap on that bike I don't even remember it all, and basically it was just idling really rich and building up so much fuel it would 4 stroke forever when you tried to rev it out. Would have to pedal it up to low speed before it would start to wind. I jetted down to a 76 last weekend and it responds very well now. It just makes no sense why I would suddenly have to downjet, and that right as it's getting cold, when I should, if anything, be going up. Weird.
Basically it's those damned SHA carbs with only one jet so you have to tune for top end and screw your low end all up.