Originally Posted by Hi-LowBlow

Hi Phil, It's Hiro.
I'm glad your son Alex has bee doing well with the car! I knew he is a great driver so not big surprise.

As for the main chassis upgrade from the tub chassis to the graphite chassis, I think it would be a good change to try. Actually the tub chassis works extremely well especially on low bite, but it's a bit heavier and keeps the motor a little bit hotter due to the less air flow.

I believe that the part number #HB70728 is the part number for older main chassis and it's already discontinued. The new part number for the new refined chassis is #67702.

Please let me know if you have any questions.
I hope i will see you at race tracks in socal (Yes, now we have choices!)

Thanks
-Hiro