HO Thunderjet Secrets? Possibly the best kept performance secret?

Here's an email I recently received from Flyin' Byran:

So I got some of those new Dash Jets last week...here's what I know...

at first I thought they were all crap... I had to grind on all 5 chassis as the crown gear was hitting part of the chassis.
all the metal gears on top were very tight. I took all the chassis apart and made a few fixes... oiled up all the gears and shafts and put valve lapping compound on the metal gears and ran them for a while. I took all the stock axles out and changed them all over to tuff ones. I put about 300 laps on each one   with the help of the niece and nephew. I spent a lot of time tweaking, testing, retesting and more tweaking....

I noticed when I was running them around the track they were not sliding like the old ones... at first I thought maybe it was the arm.. just not as much torque maybe?  But they were running some pretty good times.....   Then I was working on one of them and noticed that a loose axel I had on the table was sticking to the bottom of one of the new chassis...   I tried to see if an old one would do the same... It would not... So the reason these cars do not slide is they have magnatraction.  The Fray cars we raced at Terrys race were wider...and much lower so the magnatraction was even greater... check out this pic.. try and do this with any ordinary T-jet... as soon as I tip the track the other one slides right off... I can even go a little more vertical than in the pic...

I think the rivets that bond the plates on the bottom of the chassis are conducting the magnetism.  They must not be made of brass like the originals.