xNeo,
I do believe a high percentage of the rally striped cars you see are vinyl. nino's is vinyl. i think there are less than 10 out of hundreds that are painted. i heard of one guy getting his painted for a scant $800. most guys are paying upwards of $2,000 to get their stripes painted on.
vinyl stripes are inexpensive and look good enough to me and most others. they are not permanent and will last approx. 3-5 years depending on who you ask. of course your mileage may vary depending on how it is kept and maintained.
vinyl stripes cost anywhere from $99 to about $300 and labor to install them another $200 to $300.
finally, i do believe most stripes are not factory put on. some are dealers installed. the odds are if you see stripes down below the trunk or hood line, they are probably put on by the owner. the factory dealer stripes usually are only on the hood, roof and trunk only for the most part.
as usual, there are exceptions to every rule. galpin ford comes to mind as an exception to the last rule of thumb i stated.