LQ4 questions and Opinions

[paulk68]

Being my first LS swap I am looking for some opinions. I came across a LQ4 motor for sale. The info the seller has given is as follows

"2000-20004. Short blocking being freshened up. Has ls3 heads intake, custom ground cam(around 500hp). New ls2 pistons and heads machined .030" to get 11-1cmp ratio. New bearings, rings, oil pump, timing chain, gaskets, all hardware. Includes injectors and 90mm cable throttle body"

what do you guys think this is worth? I have some hesitation buying a used engine as it seems a little dicey to me. Are there other questions I should be asking about the motor?

Is the Aluminum block LS3 that much better?

Let me know your thoughts
Thanks