Uninstall FCPX?

I've recently "upgraded" to FCPX and am not impressed with it. When I purchased it, I was running FCS3 on my system. I noticed that my system felt a little sluggish after purchasing FCPX. I later read a forum that said Apple does not recommend running both FCP7 and FCPX on the same drive. I figured that was why my computer was running slow. I decided to wipe my computer and start fresh with a clean install of EVERYTHING. I figured it was due for a cleaning anyway. I reinstalled everything except for FCS3. I noticed how fast FCPX runs on my machine. However, I'm not happy with FCPX. I'd rather not go into why I don't like FCPX. There are too many forums bashing FCPX, and while I feel the same way, I'd rather move on. After reading Apple's recently released FAQ's about FCPX and FCP7 working together fine, I'd like to install FCS3 back on my computer. I read somewhere that Apple has stopped supporting FCS3. Does that mean when I install FCP 7.0.0 on my system, I won't be able to update to FCP 7.0.3? I'm worried that if I decide to delete FCPX and install FCS3, it won't be supported. If I leave FCPX on my machine, will I even be able to install FCS3?