This may be anecdotal evidence but the most mellow 1/12 car I have ever driven is my CRC Gen-XL with the battery transverse in the rearmost position. For a while (when my local HS was still in business...) this was my lend-a-ride for people who had never driven a 1/12 car before, but this was on medium-low traction and not tacky grip.

However, both my transverse Xti and my transverse XL suffered massively on grip. When I ran my super-mellow transverse car at the 2012 IIC, the handling was great and the only thing holding them back was me. At the 2013 IIC they were both GARBAGE on that tacky rug. I still haven't figured out why but this year I will have a rolling, ready-to-race inline car in my bag just in case.