I have been riding my bike ('88 Bianchi Trofeo) on and off since I bought it last year. I would like to start riding more often, and would like to work on the fit a little bit. I always feel like my arms are "too far in" so I measured my bars and there 42cm. I did a search and one thing I read said to measure from the center of your shoulders, and I got 46cm! I would like to buy some new bars and have been looking at the Deda RHM 01 or the Deda RHM 02 Bars (I think the only difference is the 02's are a little lighter) but they say they are 31.7mm when most stuff is 31.8mm, do I have to buy a Deda stem (like this one)thats 31.7 or does that small difference not matter? As for the chain, I'd like to get a new one as the one on it was on there from the guy I bought it from and I'm worried about it stretching and wearing out the gears. It has a 7 speed group on the back (freewheel I think) I'm looking at the "Sram 8 Spd PC850 Chain" is that a good one, and is the PC870 worth the extra money??

I have to think on a small budget unfortunately. :/
Anyway, thanks in advance!