I went LT's and will eventually do a DS...the sound alone is worth the cost of admission when it comes to LT's. Im glad I went that route as I get to enjoy it every time I start the car
I went with Pype's stepped Lt's. I started with an o/r x and still gained 15whp 20rwtq after swap as shown by Shaun@AED's dyno... plus dat sound. I think lt's are easily worth it if you have the money to spend.
you will be happier with longtubes since you will be able to feel and hear the difference. The driveshaft makes a huge difference but not as satisfactory as longtubes.