Private Car Service with Scenic Stops Lisbon to Porto

[Gourmet Gal]

Am beginning to research car services linking these two cities and would like to make a couple of short stops along the way.  Any recommendations other than Premiere Tours?  In just comparing prices they are about 30% higher than most for same service and car type.  We would prefer a premium car and there are just two of us.  

[Host Jazzbeau]

I can't recommend them because I haven't used them yet, but my TA told me about MyDayTrip.com and I am planning to use them for Lisbon-Porto and Porto-Lisbon (several days/legs each way) flanking a Douro river cruise.

[Gourmet Gal]

Thanks, I looked at their website.  Pricing is good at least.