Radiator question

I was wondering, is it Truely that much of a diff. between a single 120mm radiator and a dual one? And if i buy a single 120mm right now and upgrade to a 2nd 120mm radiator later, will it work out? Even if i did have the extra cash, to fit that dual 120mm radiator i will have to do a little modding, and im too young and dont have access to those kinda tools. I was thinking either a BIX or BIP.

I started with two BIpro single rads mounted inside my case and have replced them with one single BIPro II dual rad mounted with a Swiftech radbox on the rear of my case. I have better temperatures with the one dual and it is a lot quieter.

I would save up and get the dual rad. JMO

Thanks for the input. But its not the money factor 100 percent. Its the modding factor, i want to keep all this stuff inside of my lian li v1200. I already saw that swiftech radbox. I dont have the tools to mod this stuff or the permission from parents to hack up my case. So do u guys think a single BIP or BIX with sanyo denki plus dd tdx plus the popular swiftech pump (forgot exact name) plus resevoir, properly cool a P4 630 with overclocks up to 4ghz-4.1ghz? And future proof for conroe? I have no plans of throwing in the gpu into the loop.

Simple physics: greater surface area = more heat dissipation so yes there is a noticable difference. Sometimes you have to get a little creative to stuff it all in the case. If you can only fit a single rad you might want to get a little bit higher cfm fan on it.