First I've heard of it. IMHO, it sounds like an awful lot of work and expense. Unless, of course you're getting them for free. You can get a 4,700k McCulloch kit for less than $300 on ebay which is essentially a drop-in kit. A bunch of people on this forum (my self included) have them and the general consensus is that they work very well and are pretty easy to install.

If you decide you don't like them you can re-sell them here on this forum and get back 90% of your investment so your financial risk is pretty low.

Just my $.02