upgrade questions

I'm runninig a 9L on 14 cells at the moment in my maxx.
Which is fine for ripping up the common (park;) ) but I have started racing it now in the unlimited MT class.
Its fairly quick through the infield but the top end just can't match the BB Nitro's.
I am running 51/16 and if I gear up it won't finish the race. It also melts the solder off the 4mm tubes :eek:
As i'm using the dreaded 18.97. So I don't want to push it too much.
What are my options,
I would be happy to run 16 cells or 18 at a push as I'm using the BP torpedo chassis.
I want to keep the strobe as well so could you recomened the pinion sizes too.

I see you stock the proline shocks, can you get the stiffer spring set??

thanks in advance
:D