Depends what your future mods are. UD's are basically for people looking to squeeze every extra bit of power they can, or people just looking to basic bolt ons to gain a few ponies.. you can expect probably 10-15hp if that.. and not much of a SOTP difference if at all.
I found that while mine didn't give a lot of horsepower, I could tell there was more torque for sure. When you know your car inside and out you seem to notice every little gain. I think they were worth it, just make sure they are installed right!
i would also like to install some u/d pullies. reason is that i do alot of highway driving and the car has 3:73 gears in her and is an automatic. at 70 mph the tack sits at 2300 rpm, just would think that by dropping access drive speed would give me just a little more power and slow down the access and get better gas mileage.