hope it will help. The things we've got instantly for our Sport 16" were:
1) Rock guards (bought used from dealer, the total with installation $450).
2) Extra battery with cover mounted at A-frame (dealer bonus).
3) Surge guard with Amp meter (external, $279).
4) Screen door guards top and bottom (dealer installed, $128).
5) 1156 LED bulbs *10 ($13.50 a piece, next time would buy via Amazon - twice cheaper online).
6) Paper towel holder above kitchen sink (very useful, $5 at Walmart).
7) Hooks for kitchen towels above kitchen sink (dealer installed, $5).
8) Wire shelfs in wardrobe (DIY, approx. $50 for shelfs, free cut at Home Depot, screws, brackets).
9) Hitch coupler snap-on lock ($80).
10) Power timer to switch AC on 3 times a day in storage ($15 at Home Depot).
Working on now:
11) Noctua NF-S12A cooling fan for fridge replacement (the most annoying thing in trailer, bought two $44 at Amazon, will get mounting bracket at Home Depot).
12) Oceanair Cabinshade kitchen, bath windows and ceiling fan shades (approx. $90 a piece but make real difference in performance and look, didn't take exact measures yet).
13) Husky 4500 lbs. electric jack with wireless remote ($277 at Amazon, I think will be installing by myself).
14) Dometic upgrade kit for manual controlled ceiling AC unit (thermostat, controller, air direction box without controls, part approx. $200, labor - waiting for estimate from dealer as I want to keep warranty).
15) Advanced wax-like protection shield for entire body ($650, good for 2-3 years).
16) Water filtration system (second small faucet for pure drinking water, filter will be mounted under sink).
17) Inverter 12V
to 110V (sometimes microwave is essential, and TV may add some fun).
18) Stainless steel LP gas tanks and covers (looks really good).
19) Some stainless steel upgrades (fridge, water heater grills and shower cover).
20) Cellular and wi-fi booster (essential as e-mail access for us is must have).
21) Some outside LED lights (body mounted).
22) Fantastic 7350 or similar ceiling fan (with thermostat and rain sensor).
23) Satellite dome and receiver (not essential).
24) Solar panels and battery charging controller (not essential)
That's real shame that Airstream is saving a little dollar on simple but useful things. It's only a $200 for parts but may be much more for labor to upgrade manual AC to thermostat. At factory it would cost them only $50 in parts difference. The same with fridge fan which is itself a nonsense, the cheapest and the most loud ever made! They could add a few bucks and get a normal one, I'm not speaking about high-end, just good one. Ok, electric jack - a kind of luxury equipment, but the blinds for $5 a piece instead of good yacht-style rolling shades for "on the road" applications just doesn't make sense to me!
Good thing that almost all upgrades we're about to make can be removed and replaced with original parts that we keep in case future owner or dealership will no want to adequate count them in price or trade-in value.
If somebody have questions or ideas about what else we can upgrade in 16" Sport, I'd be happy to get them. Take care.