Upgrades to Trek 800

[old guy]

I would like to improve the shifting on this bike.
It is a 21 speed equipped like this:

Shift levers -- SRAM MRX IBS
Front De-railleur -- Shimano Tourney
Rear De-railleur -- Shimano Acera
Crank set Shimano Tourney TY-30, 28/38/48 teeth.
Narrow gauge chain with flush pins

I have spent some time adjusting the derailers without much success. It doesn’t skip gears but shifts super hard and is noisy. This bike has been very lightly used and I’m sure nothing is worn out.

Has anyone heard of chain with flared or bulged edges on plate for better shifting (Shimano Uniglide design) and would I have to change the gear set or chain rings?
Any recommendations on upgrading the twist grip shifters? Or the de-railers?

I understand the 800 is the bottom of the line for Trek, but I kind of like the bike and would not mind spending a few bucks for effective improvements especially the shifting. Any ideas are appreciated and thanks in advance.

[DaveM]

The tough part of upgrading is that changing any one part may not make much difference, you have to swap out a lot to really get better performance. Another issue is assuming there are no adjustment issues. "super hard" shifting and "noisy" tells me maybe the bike isn't 100%. Things can get bent or out of adjustment even without a lot of use. But hard to say for sure as these are very subjective terms.

But in terms of upgrading, here's what I would do:
- Don't worry about F der or crankset
- Better shifters may help, although you are fairly limited with 7 speed. I prefer the trigger style like these (http://www.jensonusa.com/store/product/SL407A04-Shimano+Stxalivio+Mc40+7+Speed.aspx ), but that's personal preference. Some people prefer the twist type.
- New rear derailleur may help. I wouldn't go super high end, but a mid range one should shift a bit crisper. Before you replace, look at the old one to see if the two pulley wheels sit in a perfect straight line with the cogs. If there's an angle, it would be the derailleur or the derailleur hanger on the frame that's bent. Fix that first.
- New chain may help a little. Again mid range Shimano or SRAM

I would consider running new cables and housing first or with any other new parts. Cheap housing can bring down shifting performance. And even good cables won't work well if they aren't lubed or if the housing has any kinks in it. This is another thing to check before you spend a lot on parts.

Finally, my standard upgrade advice: better tires and brake pads. This will make a big difference for not a lot of money. Especially if you're riding knobbies on the street. You'll be surprised how much faster and better handling some road tires will be.

[old guy]

I really appreciate the detailed suggestions and will check them with the bike one by one. Thanks again
old guy