Robin,
I am one of Manny's customers from 5 hours north of Edmonton so way further a trip than you would be looking at. I shipped my car (C6 Z06) to Manny for a project to run from 505 to about 850 hp in 2012.
Consider:
1)you do this during the winter time. Manny had the car from the end of October until spring. This allowed the project to go from an initial small hp boost to a much bigger one as the project progressed. Heh heh heh!!!!
2)Manny kept and stored the car for me.
3)it justified me making a trip to Breslau in late April the following year to test out the car before it was shipped back to me, I was able to meet Manny and his staff and to see the shop and to meet a bunch of the fellows from this website who lived in the area which was terrific fun and gave me some great memories to go along with the car. The fellowship was really special................
4)lots of cars done by Davenport out west, better to be unique and to have a Dasilva modded one......................
Take the plunge and just do it.
Cheers,
Garry