). Well, fear not, as old Forgebear is as rock-solid reliable as anything you care to put your trust in! Overdoing the metaphors a bit (and no, Friday's my only day for a slurp 
), he's like an anchor when your engine's packed in... and your boat's heading for the rocks. 
What's more, he does include some tasty dentine-killers with those well-packaged (and promptly delivered) life-saving tank and upgrade consignments. 
I've just received a Panther chassis, and metal wheels (more of that on another thread- sometime), and this very interesting TK-6.1S MFU kit.
The kit includes the wiring diagram, all the leads necessary for installation (upgrade, really), the Transmitter, and the MFU itself. All at a reasonable price. Thus:
I would have pasted in a pic of the Haribos, but I've scoffed 'em already.
and the wiring bundle:
There's: a power switch, an LED to JST connector, bullet connectors for the motors, and more besides. Take a peek.
Of course, you have to be reasonably proficient with your soldering iron to effect the upgrade, but it's a flying start to have a wiring-loom set included. Here's the wiring diag. It's almost certainly been posted before, but there's no harm in posting it again:
Anyway, the Challenger upgrade isn't a top priority at present, but as soon as I get around to it, I'll review it here.
I'm thinking of upgrading my old Chally 2 with it. When I do, I'll post the installation pros and cons here.
Andrew Haya also sells his own (commendable) version of the 6.1S as the 'Haya 6.3". But his package comes with his own unique- and fairly attractive (IMO) transmitter- but without the leads. His package is nigh on £90, and so somewhat more expensive than the Forgebear offering.
For the present, it looks like an 'either-or' world of tanks.
Thanks for the vote of confidence, Brett!. It's going to be a while, though, as I have four projects to paint first- including the Tamiya Pz IV, slated to be decked out in Finnish colours. 
