I've been thinking about replacing my 98 SC300 (165,000 miles), so I've been test driving various contenders. Here's a quick list of what I've driven so far:

2002 Lexus SC430 (50k miles, $22,000)
2003 Mercedes SLK320 (50k miles, $13,000)
2006 BMW 325i (60k miles, $18,000)
2008 Lexus IS250 AWD (40k miles, $25,000)
2006 BMW Z4 Coupe (26k miles, $22,000)
2003 Jaguar XK8 (42k miles, $20,000)

Honestly, the only car that impressed me at all in comparison to my SC300 is the Jag, but after some quick research, I think it would probably be the stupidest buy I ever made. And considering what I have owned over the past 40+ years (Triumph, Austin, Citroen, etc), that would be saying a lot.

Where folks on the Lexus forums talk mainly about mods and driving, Jaguarforums.com is absolutely FILLED with "how do I get this thing to run" threads. Not just minor things, either - things like cylinder washdown and getting the "green shower" from the top mechanism. It seems that going 2,000 miles without spending $500+ in repairs is considered a major achievement with an XK8...

At this point, I think I'll be keeping my ancient Lexus. The SC430 is tempting, but it's really not a step forward. And I absolutely love the styling of the Z4 coupe, but it's just too small and really doesn't drive that well.

Be thankful for your "old" SC's, guys - I can't seem to find a car that can compare to them!

get the XKR!

in the 20k price range ever thought about going STI or EVO? those two will make you think the SC handles like poo.

from what i've read about the IS250 is that they were to slow for what they are, otherwise they are great. yeah/ no?

look for a is350, night and day difference between the is250

maybe this will get a lot of hate but ever consider a corvette? 400 horsepower 6 speed manual lots of aftermarket support and reliable daily driver.

The only cars I could consider replacing a 98 SC300 with would be an SC430, 2000 SC400, or an 03-05 SL500. The C5 Corvette and Cadillac XLR would be nice choices too.

It's hard to beat the SC without spending a lot more money on a newer car.

The bastard child of GM. Could have had so much potential but GM botched it.
Luckily, this means the used market is good on them because their value dropped like a rock coming off the dealer floor. GM was offering $8,000 off new MRSP back when they were struggling to sell them.

Corvettes are fast and fun, but they feel like a cheap rattletrap after driving an SC.

I second the sti motion. Especially if you live somewhere that you get weather not to mention aftermarket support. But ya jag is a terrible idea...

for ~$25,000 i would look at 2003-2006 e55's, cl55's, cl600's, s55's, s600's, etc... can't beat 500hp in a mercedes imo

Don't forget to look at s2000, they like 15-17k so you have some money leftover for mods

Some good suggestions here, thanks! But at the risk of showing my age (57), those cars don't have all of what I'm looking for...

Here's what's I love about my SC300:

Styling - it's still an eye-catcher, where most "modern" coupes look like Tonka toys to me.
Inline 6 - always my first choice, low end torque is my friend. Don't like buzzy ricers.
Interior - leather and wood is a must, the more the better. Yea, I'm getting old, lol.
Space: - the two-seaters just don't have enough room for a daily summer driver.
Coupe - I don't really need or want a convertible, but a retractible could be fun.
Ride - reasonably agile, but very comfortable for the long haul.
2 doors - to me, two doors says "no car seat back there anymore!"
Reliability - Age again, but I don't fix them like I used to. My daughter says when I work on cars now, I swear and bleed too much.

Bear in mind I gave $4500 for my SC300 three years and 47,000 miles ago. And I haven't replaced anything other than routine maintenance (brakes, tires) and an alternator. It is a tough act to follow!

enough said

Eff that my dad has a 2000 jag and that baby is a boat

sounds like you want a lexus gs300/400