A Felt would not be my first motorized bicycle build. If you have built one before , go for it. If not , start with a Huffy or something alot cheaper then the Felt.
There is a pretty good learning curve to building motorized bicycles. Its not a "bolt it on and forget about it" type thing. If you learn all the ins-and-outs with a Felt its gonna be all scratched and dinged up by the time you can say "ITS DONE !"
I was pissed when I scratched my $75 Huffy Cranbrook while installing the engine. I would have probably killed someone if it was a $400+ Felt.