A re-circ valve will be fine yes.
I had mine fitted the same time as my exhaust, all supplied/fitted by stealthracing. The DV i think was around ?70, but you can fit them yourself in 10 minutes, just make sure you check the condition of all the pipes to it (vacuum line on mine had perished).
The inlet pipe is a Samco jobby provided by forge once again, although i got it through a mate for 100 notes, they're about 140 delivered from forge. Since yours is a '99 make sure to order the AGU one, or you'll have to plug a hole and swap the DV (just like i did, oops!). Took me about 2 hours to fit after all the messing about, and stopping for the rain twice.. so shouldnt take more than an hour for you.