I dont know if its just the difference in the weight of the cars or what the deal is but my Honda rides softer on generic egay sleeves with KYB GR2's than my Z does with Tein S-Tech's and Monroe Gas-Matics. Maybe its the valving in the shocks? All I know is my Z is bouncy, not like blown shock bouncy, its just all around a more harsh ride than my Honda. But like Chauncey said, in the end the difference when you buy sleeves/springs and all the parts that you need to PROPERLY lower your car like you want, vs the cost of buyin true coils and the parts you need are not that far apart. Especially if you get in on a PowerTrix group buy on their coilovers.chaunceysj wrote:i could be wrong but i knew a few people running sleeves and none of them were ever really satisfied. if you just want to lower your car they will work but i don't think id recommend them. the price may be tempting but unless you have adjustable suspension components already keep in mind that you'll need to spend more on parts to keep your camber and toe in check as well as you will need to get new struts for the lowered application (old used struts tend to blow fast, trust me). i would be much more inclined to recommend a good strut and lowering spring combo, or save up for a true coilover setup.
However i've never had sleeves so i only know he said she said reviews. if you do go with these, i would take almost any websites claims over ebay sellers. ask the seller directly maybe and look at the actual part manufacturers website to see if they carry parts for the 300zx. and pay attention to spring rates!!