German Shepherd or 2nd Rough Collie(Lassie Type)?

We already have a male 1 yr old Collie (Lassie Type) and we wanted to get a companion for him. We have always wanted a german shepherd but another collie might get along better with our collie. The collie is 4.5 months old and the german shep. is 9 weeks old. A puppy at 9 wks is a lot more work but is cheaper than the collie however, less work with the collie and it already had all its vaccinations. Not sure what to do at all. Not to mention a german shep. might eat more and be more hyper than a collie and we are on a budget. But then again the germ. shep. are great guard dogs. Also to take into consideration, would our collie and the adult german shep. get along when the ger. shep. out grows our collie? Please help us decide. Which breed/dog should we go with?