I have a 1" Top Gun Customz steel spacer, I like them, I think it was $75.
How much rear lift did you gain when you added the rear coil spacer? I bought there 3/4" rear coil spacer and the spacer itself only measured out at a 1/4". My 2.5" Rough Country spacer measured in at 2.5" and same goes for my BDS 2" rear coil spacer.
To the OP,
The Top Gun Customz steel spacer looks to be good quality and had a nice powder coat. I'm just not sure how a spacer that measures a 1/4" will raise my truck the advertised 3/4" that I had bought.
The RCX 2.5" rear space was steel as well but the finish wasn't the best. The rear spacer is held in by a grade 5 bolt that goes up from the bottom and bolts to a washer on top of the rear coil mount.
The 2" BDS rear spacer looks to be polyurethane and is held in by friction fit on the upper rear coil seat.
Me personally, I wouldn't use an aluminum spacer against steel because you'll get oxidation from two dissimilar metals touching each other. Even more so if you live in the salt belt.