HPI's small block engines are just horrid, especially with the one needle carbs.
A BB engine is a completely different experience. I started the hobby with a used Nitro Hawk that frustrated me so bad I almost gave up. Wife bought me a Savage 25 rtr one Father's day. I was amazed at the difference! So easy to operate and tune, sold the Hawk promptly and never looked back.
I say a starter box is the way to go, so much more reliable, easier to use once set up too. Less moving parts on your engine, which is one less thing to break. I started racing 1/8th nitro 5 years ago, there is no time for a B.S. roto start or pullstart. Sooner or later it will cost you a race.