Wheee! a forum member did a great write-up in the DIY section on how to do the H&R spacers and how to switch out the studs too which is very easy to do.
If you don't possess a garage, the DIY ability or the tools a shop with a lift should take between 1 to 2 hours to do the whole car for you. Wheee! and I did my spacers and new intakes in 3 1/2 hours in his garage.
Personally I wouldn't try any size spacer without longer studs.