The MI1 in my opinion is far and away a better overall package and no you won't grow out of it as quickly, especially from a performance standpoint. Don't get me wrong, the MI1 is a direct descendent of a older chassis, the Mission. It's a solid platform but older design so not as easy to work on in some respects but nothing weird....just more screws to fiddle with. Still one of the best cars I had when I was stepping up from a Tamiya TL01.
The Sprint is good but buying ball diffs isn't cheap. Internal drive ratio is also difficult to deal with using brushless motors in the 25.5 and 21.5 range.
Good luck with whatever choice you make.
BTW, I would opt for the kit version. It'll provide valuable experience for you that will come in handy later. The extra cost for assembled could go towards tires/wheels. Check out
www.philshobbyshop.com. Great prices on bodies,wheels and tires and free shipping over $50 purchase. I buy there whenever I need new VTA stuff.
