Good luck, though I would have to say that some of the most popular shops in my area have zero fluff. In contrast, I know a 'mahogany & leather' place that carefully screwed over (meaning deliberate mechanical fraud) customers for about 5 years before their reputation caught up with them. Almost got me, in fact...
I guess that I'm not sure the fancy facade is the most sound portion of your business plan. You will have to carry those upfront costs for some time. Very common for new businesses to fail by getting overextended at startup.
I like the loaner car part. This is a huge draw in my area. Invest in that, then folks will not need to spend much time in the waiting room. One guy I met who runs a repair shop has an arrangement with a used car dealer, such that every loaner car is actually for sale, and getting a test drive! Very clever...
If you want to study a very successful small auto business that made it big on reputation, customer service, and those key loaner cars, have a look at Direct Tire & Auto in the suburban Boston area. They now have 4 locations.
They are not the cheapest, but they have managed to steal substantial business from the big franchises even though they essentially did a 'full frontal assault' by doing mostly 'commodity' services (slogan: "We will Tire, Brake, Shock, and Exhaust you!").
They even opened their new locations proximate to the chains, yet they are always booked solid.
Anyways, not precisely your niche, but an interesting case study.
Generally, I would say that folks have a very low level of trust when it come to repair shops. They often rank highest among complaints to consumer agencies. Friends consult me all the time to validate estimates or inspect repairs that have been done, usually because they think they have been, or are about to get screwed. While I have actually seen many very bad operators, most of the time folks think they are getting screwed simply because they do not understand what is involved, and know full well that their ignorance COULD be capitalized upon.
For this reason, I believe that what most shops do very poorly is to educate (or at least attempt to educate) consumers about what is being done on their cars. This means pulling them out of the waiting room and into the bay to see it for themselves, always showing them the worn parts after the fact, and just generally treating them as intelligent (though perhaps ignorant) beings.
Even if they do not really understand it all, this exercise will build trust, and a viable business for the long term.
JMHO. Good luck.