mtb to road bike project idea, any point?

[RedBike]

i have been thinking about buying slicks just so I have the option.
Does it make a huge difference on road?

Yes, slick tyres will make a HUGE difference.
You might struggle with 1.3's. It all depends on how wide your wheel rims are.
Most Cross country MTBs (17mm rims) will just about take a 1.3 tyres

I wouldn't worry too much about the width. 1.5's or 1.9s will still be significantly quicker if inflated to a high pressure. (You might need to change your inner tubes over when you fit narrower tyres)

 

[RedBike]

I nearly forgot. This site shows the difference drop bars make.
http://kreuzotter.de/english/espeed.htm

If you ever see a group of roadies casually riding along the chances are they wont be on the drops. It's not very comfortable to ride along bent over double for long periods of time.

 

[mrfacetious]

ok wow thanks for all this guys. I've decided just to chuck on barends anyway as my friend is scrapping his old ones. Probably not the same but at least they give me the chance to change my position once in a while i guess. I'll buy a set of decent 26" slicks as soon as i get the cash, thanks for the link Steve, and once AGAIN for the advice Red- sorry to be a pain!
EDIT:
ok so i've been over the friends house got the barends and also more than i bargained for.
He's scrapping some old bikes, one of which has a light frame with rigid forks. So he told me I could help myself to that as well.
Nice.