The car, driven bycccIt was bought by collector Alex Thornton who said the work was a “total labour of love”.
The racing car will go on display outside Stevenage Museum in his hometown in August.
Finding the car was a bit of a “lucky coincidence” said Mr Thornton, who works in the motorsport industry.
He was visiting a friend from the 2003 team when “I spotted it in the back of a storeroom – it was all in bits, completely in pieces”.
“I think it was under the stairs for about two decades; they meant to get round to restoring it themselves.”
It was loaned to the National College for Motorsport in Towcester, Northamptonshire, so students could understand how “things go together and, apart from that, it was almost gathering dust,” he added.
After two years of nagging, he purchased it, and then the project became “a bit of a labour of love, it was quite an adventure”.
Working with restoration expert Nick Edginton, they sourced parts from across the world and it now drives like it would have done in 2003.
“It’s a really important piece of history, we’re so lucky to find it,” Mr Thornton said.
“So the last thing we want is for it to sit under a dust sheet.
“We want to get it out there and hopefully inspire the next generation of kids to go into racing.”
His dream is to have it on long-term display in Stevenage, but this cannot happen yet as it would not fit through the museum doors.
“We might be able to fire it up when it comes to Stevenage,” he added, excitedly.
