The French brand has set aside a 70 million euro budget to compete on all continents in the WRC.
Peugeot already has won three world championship titles with its rally version of the 206.
The 307 coupe-convertible (CC) will be Peugeot's new image promoter -- by order of Peugeot boss Frederic Saint-Geours.
"The new 307 CC simply has more sex appeal than its sedan version," sport division boss Corrado Provera told Automobilwoche.
He said the convertible is not a niche car since a production volume of 350,000 units is planned.
Provera said Peugeot could "credibly convey a sporty image and improve its brand image on a long-term basis" with the 307 CC.
The 307 CC's metal folding roof has been welded shut for the 300hp turbo rally version.
Peugeot expects a real return on its investment, unlike its previous involvement in Formula 1 motor sport racing.
Provera the company's rallying budget is not a large sum compared with the company's total publicity spending.
The WRC races are broadcast on television worldwide, saving Peugeot a lot of costs on advertising elsewhere.
The WRC also attracts a high proportion of younger viewers, unlike the more expensive Formula 1.
Peugeot also is recouping much of its rallying costs from sponsorship. One sponsor, the giant oil company Total, is contributing an estimated 10 million euros.
So far Peugeot's sister brand Citroen has stolen the glory in the WRC.
Citroen's older Xsara car beat the Peugeot's 307 for first place in the WRC stages at Monte Carlo in France and Karlstadt in Sweden.
"Our volume brands generally act as rivals," said PSA/Peugeot-Citroen group boss Jean-Martin Folz.
"The main thing is that both our brands are in the lead," added a Citroen executive.
VW's Skoda brand will be taking part in selected WRC races. Its budget is around 25 million euros.
Hyundai's resources are similar, and that probably won't get them anywhere close to taking over the lead.
Ford is currently cutting costs wherever it can and may withdraw from the WRC.