I would add up his Attribute points. If he is a point under a given Priority, then his Reaction should be 5 [8]; if his Attributes are correct, then his Reaction should be 4 [7].
The street samurai archetype in the core rules was 200,000+ Nuyen over; I can't say about Sledge, but his augmentations seem very different than the street samurai archetype's (he had synaptic boosters: 2, among other things).
Keep in mind that Shadowrun is not like D&D where you start out at first level. You may not be the best in the world when starting out, but you are still a professional, not a beginner. A starting character can begin play with up to 450,000 Nuyen to purchase augmentations with. Wired reflexes: 1 and reaction enhancers: 2 is pretty normal.