Need to tune, Should I buy?

Well you have to know what your doing as far as adjustments and its time consuming with a lot of tweaking to get it right. With a dyno tune its not much time on the dyno to get right. If you dont have a dyno shop close to you and like doing tuning or think you would then its not bad
 
I think you can control boost with that. You will need a wideband too. Thats another 200.

If you are not going to make any changes, I would just get a tune. Unless you like messing around with stuff like that.
 
A dyno tune is a one shot deal (and hopefully they get it right). Weather changes will effect your tune and idle. Go with a PMS or tweecer, PMS being easier to use. I like mine a lot.