It all really depends on how serious you want to get. The 8B 2.0 RTR is a great place to start, you get a good starter box and decent radio with it. Only issue with that set-up as with any RTR is the servos. When the time comes to upgrade the servos, do yourself a favor and use high quality futaba or hitec servos. The Futaba BLS452 is a great servo for steering and throttle/brake for just under $100us.
A friend told me when i started into 1/8 nitro, "you buy junk, you buy twice"
The above advice about engines is on point. I would NOT get a V-spec as a first nitro engine, there are plenty of good engines for $200-$250, until you learn don't flush $400 down the toilet. study and read the break in bible and tuning bible stickied at the top of the forum and you should be fine.