I don't think 1.425V is high but as long as you take care of the temps, it should be alright.

Why not get a 8800GTS or something instead of a Crossfire?

It depends on your ambient temp. Previously I had 1.4Vcore in an air cond room and load temp can hit up to 70C w/ stock cooler.

Most people uses BIOS 14 for the IP35 series. Every new releases of BIOS normally comes with a change log and sometimes it's only a minor fix.

For example, BIOS 22 fixes QX9450 temp issues so if you don't own a QX9450, just leave it alone

These Corsair Value Rams are definitely not meant for overclocking. If you don't have lots of cash to spend, get a Hynix FP-Y5 like what bro rozz_1291 says or get Ballistix. There are better ones but it'll also cost more.

Top up your budget a bit and go for Ballistix perhaps? I'm doing 12-4-4-4 @ 502FSB

My understanding is all new Ballistix since a while ago comes with Micron chips for sure. Unless you're really unlucky

What RAMs are you using?

More info on vdroop:
http://www.thetechrepository.com/showthread.php?t=126

Consider Foxconn Mars then

It's always better to get identical RAMs, 2 sticks instead of 4.

Clearing BIOS has nothing to do with it's lifespan. If you do it wrongly then it might.

Instead of buying/selling/trying then might as well get an E8200/E8400 for almost a 95% guaranteed 4Ghz stable overclock

Some mods are worth it and some aren't. It solely depends on the individual and if it's for extra cache, I rather skip it. In fact if I get a choice previously, I would've gotten E7xxx (3MB cache) as opposed to the E8xxx (6MB cache). Saves me quite a bit of money and all I want is FSB/clock speed overclocking

The cache doesn't play a big role in most of the things we do. Besides, it doesn't help a lot in terms of overclockability of the chip. Anyway, no harm trying

Yes, the price is around there and main difference is the cache (3MB instead of 6MB)

If budget permits then the wolfdale would be a better bet because it's 45nm (newer technology), supposedly to run cooler, overclocks better with higher FSB wall, able to run 4Ghz around 1.35V-1.4V normally and not very expensive these days.

If you're tight on budget then get the Core Duo's.

You can easily top up a bit more (RM500+) to get a used E8200 They work well and able to hit 4Ghz

I'm sorry to hear that but maybe it was something else and not the chip?

Yes, you need a 500FSB capable RAM and board to run 4Ghz as E8200 has a max. multiplier of 8x
If you don't have that 2 things then E8400 would be a better choice I tried running 8 x 533 and it booted into Windows but things started failing, lol. I guess I need to try overclocking it a bit more as I'm currently doing 502 x 8 stable.