Phil,
If you're planning on keeping the 1098 for some future project, putting some money into it may be justified.
BUT, if you plan on selling it, you might want to leave well enough alone. It's been my observation that most buyers, myself included, aren't willing to spend much on someone else's rebuild. Receipts (might) provide an insight as to what parts were used in the refresh, but there's always a question about the quality of the work. I think most of us hedge our bet by buying in on the low side. I would think that it will be hard to get out of the 1098 what you're about to spend.
Seems you've made you're mind up to move to a 1275 (good decision)...if it were me, I'd be spending my money on it.
Just my opinion,
Ray