Allen sells Walbros at NelsonPerformance.com or you may shop around. Be sure you get one that will work for your application. Do you need a factory replacement unit or an external inline pump?

Guys run 150HP shots religiously on the stock pistons but they've got their systems dialed in perfectly. If you run that much, be sure to install all the right parts, pieces and safety devices and controllers. You cannot be cheap on a nitrous kit unless you like rebuilding engines. To do it correctly you're going to spend at least $1000 on all the stuff you'll need for a wet kit.