"..... Spacers are junk and will hurt your ride."
Old thread, but this is false (**with a caveat) and I wanted to respond because I don't want people who are looking to level to feel like they have to spend a bunch of money by replacing perfectly good stock parts.
Spacers will not hurt your ride. In fact, you shouldn't feel a difference at all because you're retaining stock parts.
The caveat though is that you have to do it properly. For starters, you can't go too high. If you're looking at 2" or less, spacers work fine. The other thing is that the spacer needs to mount on top of the spring, not inside it. Most people who say spacer make the ride harsh are thinking about (or have experience with) pre-load spacers. Those will hurt your ride. Or more specifically, they'll make it stiffer because they take away some of the spring's early compression rate which is the "soft" part.
I've done lifts and levels of varying designs over the last 20+ years. If you're looking for a small bump in height, a spacer are absolutely fine. The only reason to replace the stock springs for a short lift/level is if you don't like the stock ride. Depending on the spacer kit you will need to replace the stock shocks, or add a relocation bracket. If you don't it will often "top out" the shock and create a harsh bump as it reaches its limit. This isn't a fault with the spacer kit, it's the fault of doing an incomplete job.
A spacer kit can be bought for around $200 with relocation brackets, or $300 with decent replacement struts. The Carli kit is $1200 (or $1700 with a track bar). Which BTW you can get one from Summit Racing for $200.
Thuren is $980 with Bilstein shocks and a track bar so that price is more reasonable but still more expensive than a spacer kit. If you don't like the stock ride, this is a decent option, but you won't have a 1" or 1.5" option (except diesel which does have 1" option).
TLDR;
Spacers won't hurt your ride if you do a proper job. They offer more height options, and are considerably cheaper than replacing OEM prats.