Mountain Biking - Swapping Parts

I have a 1999 Specialized Stumpjumper FSR XC and a 2002 Giant AC Air. Although the Giat is a newer bike, I really like the frame & feeling of the Spec SJ, but thefront fork & rear shock on the Giant are higher quality. So, I want to swap parts on each bike. I am comfortable doing maintenance and the parts all measure about the same, so will not be altering the height or other dimensions of the bike.

However, I am asking for anyone's opinion as to whether or not swapping parts is a good idea or am I just better of buying a new front and rear shock?

Also, if anyone could share their experiences, what to watch out for, I would appreciate the feedback.

You need to check the eye to eye length on the rear shock and make sure the stroke is the same. Close doesn't really cut it on that one.

So, as long as the full extension of each stock is the same, measuring on center from each hole, I should be OK? But I have to be exact?

Stroke length is important too, as LowCel said. And you can't judge by the 'customary' stroke for that brand shock's eye-to-eye length, as some OEM versions were different. You'll need to either be able to look it up on the web or physically collapse it all the way and measure.

Yes you have to be exact. You also need to make sure the stroke is the same.

*edit - beat to the punch... :o