Hi Canadian Dougie. I can only base an answer to the which kit? question on my own experience of building my Vitesse based Sammio Spyder.
It took me two years to finish, which is longer than I anticipated but I'm led to believe it's pretty quick by most kit car build standards. Apparently some people take a decade or more and many never complete their builds.
More than half of my build time was spent renovating a rotten donor, and if I'd spent twice as much on a sound Vitesse in the first place I'd have finished the car in about a year.
Assuming your donor isn't a rot box and is already roadworthy there are about twelve simple(!) steps as follows:
1/ Strip donor car of interior, body tub and bonnet and sell unwanted parts on ebay, possibly for more than you paid for the donor.
2/ Cut bulkhead down to recommended level (I'd profile mine to match the underside of the body shell if I built another).
3/ Lower suspension to desired ride height.
4/ Make/buy lowered floors and fit to chassis.
5/ Bolt frame onto chassis/bulkhead, fit fuel tank, sort out electrics, handbrake, seat belt mounts and fuel supply.
6/ Test drive 'moon rover' on private land if desired (see Phil J's other youtube vid's).
7/ Bond body shell onto chassis/frame, ply line interior and create dashboard.
8/ Fit and fettle bonnet, flyscreen and lights.
9/ Prep and paint if required.
10/ Fit seats/belts/interior trim and instruments to personal taste.
11/ Add petrol, sorry,
gas, take a deep breath and drive to MOT (or equivalent).
12/ Enjoy.
My build thread shows that I bonded on the body on 12th July 2012, and took the finished car for its mot on 1st July 2013, but Patoune manages to put one of these together in about four weeks (although he is doing it professionally).
As for the choice of kit once it's finished, some people seem to like the fixed wings with bonnet opening of the Miglia, while others prefer the original clam shell bonnet design of the Sammio. For my part, I was bloody glad of the removable front end when my clutch failed on the dyno and I had to take the engine out.
Here's a few pictures of my build, and if you haven't already seen it my build thread can be found by clicking the 'views' button to the right of the screen on the Sammio Ribble and Miglia builds page, which'll pop it to the top.
Get inspired by one of these -
Then find you can actually buy one of these -
So you take one of these -
Sort out a bit of this -
To get it looking a bit like this -
Then glue this on -
Spend 'king ages doing this -
To end up with something like this -
Make some new friends along the way and go do some of this -
Ultimately, you pays your money, you takes your choice.
Good luck, eh?