First ride on my Hardrock was..
 

...tiring.

It's a nice bike and it has potential, but some things need to change. First of all, those gigantic knobby tires HAVE to go because I put so much effort in to pedaling and it feels like I am going nowhere. Also, the stock 'grips' really suck; the don't grip at all and provide no cushion. I might add bar ends for the extra hand positions as well. I forgot to check if it has eyelets for racks, but I might add those as well. Oh, and the seat is extremely uncomfortable, but I'll wait a while because I've been bikeless for a month, and yes, I have padded bike shorts.

Other than that the bike is pretty solid and functions well. I do miss my 1.2 though.. :cry:

What are the smallest tires that will fit the hardrock?
Could I swap the shocks in the front for a carbon fork? This would be way down the road, but I might as well ask.

What size tires do you have now? Just swapping to wide slicks will improve your on-road speed a bit for the same amount of effort.

Ergon grips- 'nuff said.

I'd go with a rigid steel over a carbon fork myself...

According to your sig line, you have a Trek hybrid. Why not just that as a commuter? It already has about half of the mods that your Hardrock will require to make it more road worthy.

I bought the Hardrock so I gave it back to my brother. And I'm not exactly sure, but they look twice the size of the 35c tires on the Trek.

Does your Hardrock have 26" rims or is it a 29er? I have a Hardrock 29er and use 700x38 tires. I'm easily 4 to 5mph faster with the same effort on the street tires. It should have eyelets for a rack. They are on the seat stays about three inches down from the seat tube. If you have disc brakes you would need the rack designed for them.

On the website it says 26" rims. And this one doesn't have disc breaks.

I would guess you have 2.2 inch tires, probably can go down to 1.5" tires without getting new rims. I would probably just ask at the bike shop to make sure, but you'll probably be able to go down to 1.5" or 1.25". You put some slicks on there and you'll be faster for sure, maybe a couple mph or possible twice that. You can put a rigid fork on it, if it has suspension or lock out the fork. Taking off the suspension fork will probably take off 4 pounds of weight, maybe more depending on how old the bike is or you can lockout the fork to make it roll better when standing or climbing.

I bought a HR late this past winter and have commuted on it a few times. It really beats me up! I thought of changing out the fork to one that locks out and maybe road skicks but haven't as of yet. I am dumping too much into other bikes right now.