I admire your enthusiasm, but I think somebody needs to tell you that your plan is unwise. If you wanted to keep the bike and ride it, then I would say that it was a great plan, as it's a decent frame and it will ride very well. However if you're going to sell it, you have to look at what older FS bikes sell for, which isn't very much. I can't see from your pictures whether it has rear disc tabs - if not, even worse, but even if it has disc tabs it's not going to sell for more than £200-300. And for every extra £100 you spend on shiny newish parts, you will add maybe £20-30 to the sale value. In the end, it's still a 1999 bike, even if the parts are all more recent upgrades.
I have a 1998 Marin East Peak which was £1,000 in its day and was rated at 5 stars, best on test and 'simply superb' in an MBR feature. It's in good condition, very original, quite nice to ride, paintwork excellent. I expect it will raise £150-200 on eBay.
I have a 1998 Marin East Peak which was £1,000 in its day and was rated at 5 stars, best on test and 'simply superb' in an MBR feature. It's in good condition, very original, quite nice to ride, paintwork excellent. I expect it will raise £150-200 on eBay.