ProTeam Corvettes had one when I last visited their showrooms for a walk-through. I'm not a big fan of the boxy look either. As for the performance that it was capable of achieving, I'd have to figure that adding only 25hp would be very underrated based on two things.
1) The size of the turbo is freakin' huge on that thing (relative to today's turbos).
2) If the car is in fact capable of 144mph, it's going to be needing more than 25hp over the base engine's hp rating, as the base model was only capable of around 126mph. 25hp ain't gonna bump you almost +20mph in the top end.
This is driving me crazy! I know I read an article in 'vette magazine about the Duntov turbo, however I can't find it now! Oh well. I recall that they used an L-82 block (at least in development, not sure about production) because they needed it stronger to make reliable boost. In fact I'm almost sure they never used the L-81 in the Duntov turbos.
L-82 engine+turbo+aerodynamic body (?)+different gearing (?) could possibly = 144mph top speed. In theory at least.
P.S. I just remembered another fact. They had to cut a vent above the turbo to keep it cool. It melted through some hoods during development!
P.P.S.- Ugh I just read on a quick search that the turbo gave the engine 70hp, and the block was an L-48!! This is driving me nuts. I contacted 'vette magazine to see if they can shine a little light on this. Stay tuned.
There's a guy in my area that has an Avanti as his daily driver during the nice weather, and damn if that thing doesn't look and sound nice. I think they came with Ford 351C engines, if I'm not mistaken, and I believe they were all hand built. That turbo vette did look a bit like an Avanti.
1959 black 270hp (9/2/69) 1981 Beige L81(10/20/80)
The original Avantis came with Studebaker 289 V8s in 3 levels. R1 was a single 4 bbl; R2 was a blow through Paxton supercharger with a carb bonnet and R3 was a higher boost Paxton with a carb enclosure. When Studebaker ceased production and sold the car to the Avanti Motors Corp. they began using 350 Chevys supplied directly from GM. These were regular production engines that were EPA certified by GM and the same thing available in Chevroler passenger cars.