Is the Tornado chip a DIY job?
The hotwire ECU is the 14CUX. The mapping & program is contained in a PROM, such as a 27256, with 262,144 bits. very small by todays standards.. Some 14CUX ECU have the PROMs soldered onto the circuit board, some are plugged into a socket. If your ECU has the socket, then the original PROM can be removed (unplugged) and the Tornado chip can be plugged in as a replacement. I would think that most of the later ECU have the socket arrangement.
I don't have a Tornado chip, but have the Optimax chip, which originates from the same source as the Tornado. The arrangement is a circuit board with a PROM and decoder chip on it, this assembly plugs into the 14CUX ECU replacing the original PROM. I believe the contents of the Tornado and Optimax PROMs are encoded in order to prevent copies being simply made and used.
If your ECU has a soldered PROM it is possible to remove it and replace it with a socket, however it is a fiddly job with some risk. I have replaced a few, but it is not for the faint hearted.
While the PROM contains 262,144 bits, the program and data fits into one half of this store, and the other half is filled with a copy. More information can be found on Piston Heads via various historic threads by TVR folk
So the answer is 'yes' it can be a DIY job, with the caveat regarding the way the original PROM is affixed to the PCB