I'll give you a perspective over the last 4 cars I've owned. It's interesting because along the way you learn different things by way of comparison.
1997 WRX
2004 RX8
2005 Integra Type-S
2007 MX5 (current)
The WRX was worked and fun for what it was, but was ultimately uninspiring. The RX8 was smooth as butter and sounded amazing to drive. I had forgotten what RWD felt like and it was awesome. In the end, I felt the performance didn't match the petrol guzzling and it went. The Integra was interesting in that even though it was FWD, it was surprisingly razor sharp. It had enough power (154kw) for a FWD and was well balanced. All jokes aside, VTEC is awesome, its highly addictive and very clever in simplicity. It had to go for a few reasons, financial was one. Shoot to now, the Mx5. By far the lowest powered....but by far the most fun! The feedback, handling, balance, chuckability and one-ness are very hard to match, and I place a huge amount of emphasis on these things. Actually the power to weight is more than enough, but if were younger I might crave for a smidgin more, but seriously, it doesn't need it.
For me, it's not hard to imagine what a wonderful car the S2000 would be; 177kW PLUS RWD makes my mouth water, but it's not every ones cup of tea. The two obvious downsides are; 1. high revving is almost a requisite and 2. live-ability in a convertible if your tall. As for reliability, at last count Honda was up to like 15m engines worldwide with not one reported engine failure from factory (un-moddified).
In your case, you are going from torque monster FWD to a high revving RWD car. Very different. Upgrade or downgrade is an irrelevance, you need to be in the car you love. If your going down the S2000 path, you'll have to work it a lot more, but then to me, that's what driving is all about.