first off... Welcome to the site!!!
i actually have a 2003 coupe with CC and i LOVE IT!!! you are in for a great time if you decide to buy it.
like all used cars, be very careful of what you are buying
know that you only have two major things to worry about... you will have to replace the clutch if the owner didn't and it could run you 2500+. also know that the F1 pump could fail and if you do not replace the F1 pump relay often this could end up being a problem. drive belts sometimes crack if it was a winter state car. (OK that was probably more that two but you get the idea
other than, you are all set. just change the oil as often as you can and that's that. the service can be done at a GOOD mechanic or a Italian specialist. so don't worry about CRAZY maintenance Ferrari like troubles.
the car has character and it really is a drivers car. balance if almost perfect, the Ferrari engine is a delight, brakes could be better .but you can buy after market pads (ceramic/kevlar) and that fixes that.
over all i can tell you that i had a 5 series, and a Z4 BMW a porsche, probably all the VW car ever maid including the tuareg. the Maserati is the best over all sports car for the price.
you can buy something faster, smaller , bigger, smother, cheaper , exotic...but their is only one Maserati.
hope to see you soon with new post and Welcome to the family.
-willie