Another thing people do is get a bigger or "over sized" cooling head. The only issue with that is making sure you buy one that fits correctly, and they can be kind of costly, $35 us would be the cheapest but i've seen some for $85 retail.
On the upgrade question, i would get a carbon or alum battery tray. that would save a good amout of weight.

Or your could just sell the engine. it seems like they are being more and more people saying how bad that engine is. I loved my 12Rss b4 i messed up the heat sink (colling head whatever)& piston/sleve. so i got a OS. 18 tz/tx fits perfect but have to adjust my car for the power. hope this help some