Hi Paul
I fitted a Roadrunner Hi Torq starter to my road car in Nov 2010. Since the it has covered about 25,000miles without issue. They happily fitted the extra terminal on the solenoid as that car still runs a ballast resistor circuit when starting. Fitting wasn't as easy as a standard but using cap screws helped. Note they still use the three mounting holes. Roadrunner are based in Tauranga, NZ but don't know if they have an agent in your part of the world.
https://www.roadrunner-starters.com/col ... sh_triumph. They still list the Sprint model RS205D.
However, for all of the 100+ race meetings I ran my Maple Sprint in NZ, I never found the need to switch from a standard starter.
I was conscious that under bonnet heat was of concern so I ran an aluminum tray between the spoiler and the subframe, had extra air inlet holes in the front and for the most part ran without the two inner headlamps. That certainly helped with increasing airflow past the engine. I also had the 12" electric radiator fan wired in with manual override to avoid underbonnet temperature rise after stopping in the pits. The EWP115 was the last extra I fitted - superb kit.