The Maruzen L96. It's very expensive and discontinued, but you can find it at a couple places for $350-400. Your other option is to get a clone L96 (all other brands are clones, and have similar shitty quality) and replace everything except the externals: this would include: inner barrel, hop up, trigger mech, and cylinder set. This could run you as little as $350-400 + the $150 for the gun/scope. That would give you a decent setup, although the externals would not be as high quality, and you can easily go higher on better internal parts.
Keep in mind for a clone to be any good all the internals have to be replaced and for it to feel good all the externals need to be replaced and the stock needs to be worked on ($450 for barrel/receiver/endcap+elbow grease). Whereas the Maruzen shoots accurately out of the box