which upgrade is the best?

hi everyone im new to these forums and motorized bicycles in general, i ordered a 66/80 cc engine kit and intend to put it on a 29" bike this kit, and this bike specifically Walmart.com: Genesis 29" Men's Mountain Bike: Bikes & Riding Toys

Jet 80cc 2 Stroke Bicycle Motor -Jet 80cc 2 Stroke Bicycle Engine Kit

i haven't bought the bike yet, so i figured i'd ask people with more experience if they see any problems with that. the exhaust pipe looks like it could be a tight fit because of the big tires. i would like to ride the back roads from MA to NH when the weather gets better to visit my friends and thought motorized bicycles would be a fun and cheap way to do that.

anyways the site i ordered from gave me a bit of a hard time and the guy who helped me sort it out offered to throw in the carburetor i had asked him about, since i was curious if it was worth the extra investment, i think this is the one i'll be getting if he follows through

http://www.kingsmotorbikes.com/bike-motor-engine-high-performance-carb-genb.htm

so aside from will the motor fit on that bike properly,safely, and with out removing the functionality of the bicycle its self (like i said 50 mile or so travel if the motor dies for some reason id like to be able to pedal still), my next question would be what's the best parts to upgrade on these things?

i was considering getting this: Sick Bike Parts

but i'm unsure if its worth it/will provide a noticeable performance increase, or if my moneys better spent elsewhere, or if from the looks of it, it will even fit comfortably on that bike frame.

thanks everyone who takes the time to read and respond and hopefully eventually i'll be able to start contributing and helping others myself

Hammond Egger said:

If you're going to ride a mb 50 miles your first upgrade or investment should be a good took kit and somewhere to carry it. That's a long way to pedal a bike with a motor on it.

Click to expand...

while i appreciate the concern i never travel out of city with out a basic set of tools

but for a performance boost what would be the best part to upgrade?

thanks.

http://motorbicycling.com/f15/i-think-i-finally-nailed-28689.html#post272219

success!

turns out sprocket adapter and good tugnuts were the best money spent imo.