I am in the market of upgrading my stock RC18R to Lipo. Question is...do I need the Novak 2-Cell external lipo cut-off or can I go without? My car is not for bashing and will only be run at a track. I plan to top it off after each qualifier which is approximately 6-7 minutes of use or at most every 2 qualifiers. Is it possible to go below minimum voltage in say a 1550mah lipo after that time? Thanks in advance...

Since you're racing and running is timed, you don't really need a smart stop.
You need to make a short, timed run on the track and see what goes back into the lipo. Then you can figure a mah/min and have a better idea on where you'll be after 6 - 7 min. From what I've seen, this usually turns out to be numbers like 120-150mah/min so I don't see where you'll have a prob. But I'd find out rather than taking any chances.

Use the money for something else.

Thanks Duster...the money saving is one thing but not adding any more weight, even a few grams is another. I will do some test runs after I get the lipo. I may decide to get a new ESC with a lipo cut-off eventually so I didn't want to buy something now that I may not use for a while.