I'll try to answer all the question that you had in this thread! I have an Evo that I just received last month.
1) Storage space under the seat is rather small, less than a cubic foot. Mine is full when I put in my tool kit, first aid kit, rain pants and rain jacket. Get a trunk! I got a Bestem (see below)
2) Acceleration is fast. I'm 250 lbs, and I can get off the line at a stop light faster than the cars around me. This blows away my Taotao ATM50-A1 Stealth 80cc (upgraded from 49cc).
3) MPG: I've only got about 200 km (125 mi) on the bike, but MPG running about 55-60 mpg with upgrades listed below.
4) So, far the reliability is excellent. Engine always starts even in cold weather. Purrs. Roars too if you want it too.
5) Doesn't come with a trunk, but you can mount a giant Bestem T-Box on the back like I did.
6) Killer looks. Streamlined and nice curves.
7) Don't know about gear replacement...
8) Engine and plugs accessible when the seat is removed. Easy to remove the seat. The air filter is mounted toward the front of the seat, but you can work around it. Under-seat compartment is at the back and lifts out with the seat.
9) Evo tire is a 130/60-13 low-profile performance type. Rims are 13".
My Evo was $930.91 (incl shipping, lift gate svce, residential delivery, everything out the door) from familygokarts.com (excellent customer service by the way).
I had Rolling Wrench in Denver do the PDI after I assembled most of the bike. The headlight assembly/cowling can be a bear to attach--two man job.
Videos of my Evo being assembled:
https://www.youtube.com/user/activity10cc
Some have mentioned in this thread that they got crap Evos. You have to do the necessary upgrades, otherwise they can be lemon-like.
My upgrade list:
- Motobatt MBTZ10S (12V 8.6 Amp) 190CCA Factory Activated QuadFlex AGM Battery
- Bestem T-Box TBOX-2012-BLU Blue 20" X 10.5" X 16" Scooter trunk
- NGK Iridium spark plug
- Naraku CDI box
- fuel filter, Helix vacuum line and fuel line kit
- LED wiring from trunk to brake light harness
- red ignition coil
- magnetic drain plugs for gear oil/engine oil
- tire valve stem upgrade
Hope this helps!