[R] Load Tawny package on R 2.15.3

[Tstudent]

> I have no specific expertise here, but I just wanted to point out that
> this sounds like a losing strategy long term: As new packages and
> newer versions of packages come out that fix bugs and add features,
> you'll be unable to use them because you'll be stuck with 2.15.3 . I
> suggest you bite the bullet and follow the experts' advice to get
> things working with the current R version now.
> 
> Cheers,
> Bert
> 
> >
> > ______________________________________________
> > R-help <at> r-project.org mailing list
> > https://stat.ethz.ch/mailman/listinfo/r-help
> > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> > and provide commented, minimal, self-contained, reproducible code.
> 


It seems that the only possibility for me is to install R 3.0
So i have a question. 
Now i use R 2.15.3 and Rstudio (which is linked to R 2.15.3)
Can i install R 3.0 in another directory but leave R 2.15.3 as default or
primary R  ? Any problems to do this? Something to be careful?