Your problem could be several things, but is NOT uncommon with our cars... Stealth or VR4.
My SL never had a problem, but my 95VR4 did... grinding when shifting hard, sometimes normal shifting form 1-2 or 2-3, but rarely anything else. (WORSE WHEN COLD)
The most common thought, the synchros are going bad.
The first fix I'd suggest is the easiest and costs very little.
Get your $20 oil change at the dealership (that's what it costs me with the coupons), and BRING THEM synthetic fluids to use in your tranny.
One of the most popular, if you didn't already know.. is Redline or Mobile 1.
The cost from Red-line (from memory) is about $7 per quart
It'll take about 5 quarts.
Buy 3 quarts of Redline MTL (from red-line site, or many DSM vendors)
Buy 3 quarts of MT90 50/50.
A 50/50 mix is about right for the transmission.
They'll have some left-over.
This made my shifting... much smoother, and it'll extend the life of your tranny, and not having to get new synchros.
It got smoother and smoother for a few hundred miles, then leveled off to very acceptable (ie... little grinding now) I have 82,000 miles on the car.
Hope, this helps.
Scott